Summarize the following:
Go to http://kernel.ubuntu.com/~kernel-ppa/mainline/ in your computer's web browser. Scroll down until you find the link to the kernel version number you want to install, then click it to open its page. As of August 2018, the newest kernel is version 4.18. You can find it at the very bottom of the page under the v4.18 link. Usually the top list of kernel (.deb) files will work for your computer, but if you see a heading that contains files which seem better suited to your computer than the top heading, you may want to use its files instead. Each heading on the page should say "Build for [architecture] succeeded" where "architecture" refers to your computer's system architecture (32-bit or 64-bit). Click each kernel file's link to do so . You'll need the "headers" file marked for all versions, the "image" file with "generic" in its name (avoid the "low latency" versions of these files), and the "modules" file with "generic" in its name. For example, to download the necessary files for kernel 4.18, you would click the following links:  linux-headers-4.18.0-041800_4.18.0-041800.201808122131_all.deb linux-image-unsigned-4.18.0-041800-generic_4.18.0-041800.201808122131_amd64.deb linux-modules-4.18.0-041800-generic_4.18.0-041800.201808122131_amd64.deb Click the black Terminal icon on the left side of the screen. This will open the Terminal window. You can also press Ctrl+Alt+T to open Terminal. Type in cd Downloads and press ↵ Enter. If your default "Downloads" location for your web browser differs from the "Downloads" folder, replace "Downloads" with the path to the folder into which your kernel files downloaded. If you have any .deb files not related to the kernel installation in this directory, either move them or delete them before proceeding. Type in sudo dpkg -i *.deb and press ↵ Enter. Type in the password you use to log into your computer, then press ↵ Enter. You won't see any characters or stars appear while typing. This may take a few minutes. Once you see the "Downloads" directory tag reappear next to your name at the bottom of the window, you can proceed. Click the "Menu" {"smallUrl":"https:\/\/www.wikihow.com\/images\/8\/82\/Android7dropdown.png","bigUrl":"\/images\/thumb\/8\/82\/Android7dropdown.png\/30px-Android7dropdown.png","smallWidth":460,"smallHeight":460,"bigWidth":"30","bigHeight":"30","licensing":"<div class=\"mw-parser-output\"><p>I edited this screenshot of an Android icon.\n<\/p><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/en.wikipedia.org\/wiki\/Fair_use\">Fair Use<\/a><br>\n<\/p><\/div>"} icon in the top-right corner of the screen, then click the "Power" {"smallUrl":"https:\/\/www.wikihow.com\/images\/5\/5d\/Windowspower.png","bigUrl":"\/images\/thumb\/5\/5d\/Windowspower.png\/30px-Windowspower.png","smallWidth":460,"smallHeight":460,"bigWidth":"30","bigHeight":"30","licensing":"<div class=\"mw-parser-output\"><p>I edited this screenshot of a Windows icon.\n<\/p><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/en.wikipedia.org\/wiki\/Public_domain\">Public Domain<\/a><br>\n<\/p><\/div>"} icon and click Restart in the resulting pop-up window. You can double-check that Ubuntu's installation of your kernel was successful by opening Terminal and entering uname -sr. If this command shows you a number that matches the version number of the kernel you downloaded, your kernel has successfully updated. If you don't see the correct kernel number here, you may have downloaded the wrong files for your computer. Delete the .deb files from your "Downloads" folder, then go back to the list of kernel files and try downloading them from under a different heading.

Summary:
Open the Ubuntu kernel list. Select a kernel version. Find the kernel for your computer. Download the kernel files. Open Terminal. Switch to your default "Downloads" directory. Prompt Ubuntu to open the .deb files. Enter your password when asked. Wait for Ubuntu to finish installing the kernel. Reboot your computer. Check your current kernel.