I installed GLWF succesfully. I can prove that since this program compiles:

```
#include <GLFW/glfw3.h>

int main(void)
{
    GLFWwindow* window;

    /* Initialize the library */
    if (!glfwInit())
        return -1;

    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }

    /* Make the window's context current */
    glfwMakeContextCurrent(window);

    /* Loop until the user closes the window */
    while (!glfwWindowShouldClose(window))
    {
        /* Render here */
        glClear(GL_COLOR_BUFFER_BIT);

        /* Swap front and back buffers */
        glfwSwapBuffers(window);

        /* Poll for and process events */
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
}

```

Then i used these commands in order to install glad:

```
git clone https://github.com/Dav1dde/glad.git
cd glad
cmake ./
make
sudo cp -a include /usr/local/

```

When i tried to execute this program:

```
#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <iostream>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);

// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

const char *vertexShaderSource = "#version 330 core\n"
    "layout (location = 0) in vec3 aPos;\n"
    "void main()\n"
    "{\n"
    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
    "}\0";
const char *fragmentShaderSource = "#version 330 core\n"
    "out vec4 FragColor;\n"
    "void main()\n"
    "{\n"
    "   FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
    "}\n\0";

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

    // glfw window creation
    // --------------------
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
    if (window == NULL)
    {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    // glad: load all OpenGL function pointers
    // ---------------------------------------
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    // build and compile our shader program
    // ------------------------------------
    // vertex shader
    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);
    // check for shader compile errors
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    // fragment shader
    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);
    // check for shader compile errors
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }
    // link shaders
    unsigned int shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);
    // check for linking errors
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }
    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    // set up vertex data (and buffer(s)) and configure vertex attributes
    // ------------------------------------------------------------------
    float vertices[] = {
         0.5f,  0.5f, 0.0f,  // top right
         0.5f, -0.5f, 0.0f,  // bottom right
        -0.5f, -0.5f, 0.0f,  // bottom left
        -0.5f,  0.5f, 0.0f   // top left 
    };
    unsigned int indices[] = {  // note that we start from 0!
        0, 1, 3,  // first Triangle
        1, 2, 3   // second Triangle
    };
    unsigned int VBO, VAO, EBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);
    // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    // note that this is allowed, the call to glVertexAttribPointer registered VBO as the vertex attribute's bound vertex buffer object so afterwards we can safely unbind
    glBindBuffer(GL_ARRAY_BUFFER, 0); 

    // remember: do NOT unbind the EBO while a VAO is active as the bound element buffer object IS stored in the VAO; keep the EBO bound.
    //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

    // You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
    // VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
    glBindVertexArray(0); 

    // uncomment this call to draw in wireframe polygons.
    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

    // render loop
    // -----------
    while (!glfwWindowShouldClose(window))
    {
        // input
        // -----
        processInput(window);

        // render
        // ------
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // draw our first triangle
        glUseProgram(shaderProgram);
        glBindVertexArray(VAO); // seeing as we only have a single VAO there's no need to bind it every time, but we'll do so to keep things a bit more organized
        //glDrawArrays(GL_TRIANGLES, 0, 6);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        // glBindVertexArray(0); // no need to unbind it every time 

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    // optional: de-allocate all resources once they've outlived their purpose:
    // ------------------------------------------------------------------------
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteBuffers(1, &EBO);
    glDeleteProgram(shaderProgram);

    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}

// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow *window)
{
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
        glfwSetWindowShouldClose(window, true);
}

// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    // make sure the viewport matches the new window dimensions; note that width and 
    // height will be significantly larger than specified on retina displays.
    glViewport(0, 0, width, height);
}

```

I got these errors:

```
/usr/bin/ld: /tmp/ccDMX5H7.o: in function `main':
triangle.c:(.text+0xe9): undefined reference to `gladLoadGLLoader'
/usr/bin/ld: triangle.c:(.text+0x12b): undefined reference to `glad_glCreateShader'
/usr/bin/ld: triangle.c:(.text+0x13f): undefined reference to `glad_glShaderSource'
/usr/bin/ld: triangle.c:(.text+0x162): undefined reference to `glad_glCompileShader'
/usr/bin/ld: triangle.c:(.text+0x173): undefined reference to `glad_glGetShaderiv'
/usr/bin/ld: triangle.c:(.text+0x19a): undefined reference to `glad_glGetShaderInfoLog'
/usr/bin/ld: triangle.c:(.text+0x1fd): undefined reference to `glad_glCreateShader'
/usr/bin/ld: triangle.c:(.text+0x211): undefined reference to `glad_glShaderSource'
/usr/bin/ld: triangle.c:(.text+0x234): undefined reference to `glad_glCompileShader'
/usr/bin/ld: triangle.c:(.text+0x245): undefined reference to `glad_glGetShaderiv'
/usr/bin/ld: triangle.c:(.text+0x26c): undefined reference to `glad_glGetShaderInfoLog'
/usr/bin/ld: triangle.c:(.text+0x2cf): undefined reference to `glad_glCreateProgram'
/usr/bin/ld: triangle.c:(.text+0x2de): undefined reference to `glad_glAttachShader'
/usr/bin/ld: triangle.c:(.text+0x2f7): undefined reference to `glad_glAttachShader'
/usr/bin/ld: triangle.c:(.text+0x310): undefined reference to `glad_glLinkProgram'
/usr/bin/ld: triangle.c:(.text+0x321): undefined reference to `glad_glGetProgramiv'
/usr/bin/ld: triangle.c:(.text+0x348): undefined reference to `glad_glGetProgramInfoLog'
/usr/bin/ld: triangle.c:(.text+0x3ab): undefined reference to `glad_glDeleteShader'
/usr/bin/ld: triangle.c:(.text+0x3bc): undefined reference to `glad_glDeleteShader'
/usr/bin/ld: triangle.c:(.text+0x4b9): undefined reference to `glad_glGenVertexArrays'
/usr/bin/ld: triangle.c:(.text+0x4d1): undefined reference to `glad_glGenBuffers'
/usr/bin/ld: triangle.c:(.text+0x4e9): undefined reference to `glad_glGenBuffers'
/usr/bin/ld: triangle.c:(.text+0x501): undefined reference to `glad_glBindVertexArray'
/usr/bin/ld: triangle.c:(.text+0x512): undefined reference to `glad_glBindBuffer'
/usr/bin/ld: triangle.c:(.text+0x528): undefined reference to `glad_glBufferData'
/usr/bin/ld: triangle.c:(.text+0x54b): undefined reference to `glad_glBindBuffer'
/usr/bin/ld: triangle.c:(.text+0x561): undefined reference to `glad_glBufferData'
/usr/bin/ld: triangle.c:(.text+0x584): undefined reference to `glad_glVertexAttribPointer'
/usr/bin/ld: triangle.c:(.text+0x5ad): undefined reference to `glad_glEnableVertexAttribArray'
/usr/bin/ld: triangle.c:(.text+0x5bb): undefined reference to `glad_glBindBuffer'
/usr/bin/ld: triangle.c:(.text+0x5ce): undefined reference to `glad_glBindVertexArray'
/usr/bin/ld: triangle.c:(.text+0x607): undefined reference to `glad_glClearColor'
/usr/bin/ld: triangle.c:(.text+0x630): undefined reference to `glad_glClear'
/usr/bin/ld: triangle.c:(.text+0x63e): undefined reference to `glad_glUseProgram'
/usr/bin/ld: triangle.c:(.text+0x64f): undefined reference to `glad_glBindVertexArray'
/usr/bin/ld: triangle.c:(.text+0x660): undefined reference to `glad_glDrawElements'
/usr/bin/ld: triangle.c:(.text+0x696): undefined reference to `glad_glDeleteVertexArrays'
/usr/bin/ld: triangle.c:(.text+0x6ae): undefined reference to `glad_glDeleteBuffers'
/usr/bin/ld: triangle.c:(.text+0x6c6): undefined reference to `glad_glDeleteBuffers'
/usr/bin/ld: triangle.c:(.text+0x6de): undefined reference to `glad_glDeleteProgram'
/usr/bin/ld: /tmp/ccDMX5H7.o: in function `framebuffer_size_callback(GLFWwindow*, int, int)':
triangle.c:(.text+0x764): undefined reference to `glad_glViewport'
collect2: error: ld returned 1 exit status

```

I compiled the program with this command:

```
g++ triangle.c -o triangle -Wall -lGL -lGLU -lglut -lGLEW -lglfw -lX11 -lXxf86vm -lXrandr -lpthread -lXi -ldl -lXinerama -lXcursor

```

EDIT:
I used these two resources to perform the installation of the libraries:
<https://www.youtube.com/watch?v=ZwaHQ6c-ma0>

<https://shnoh171.github.io/gpu%20and%20gpu%20programming/2019/08/26/installing-glfw-on-ubuntu.html>