Question: I am trying to understand things like linkers and loaders better.

What area of computer science do they belong to? Compiler, Operating System, Computer Architecture?

Where do linkers and loaders come into play during development?

Answer: 
To find out more about linkers, I think they'll generally be discussed in combination with compilers. They are for knitting your various modules together into a cohesive unit, finalizing addresses within that code. Some may even try to perform optimizations.

To find out more about loaders, I think they'll generally be discussed in combination with writing compilers for particular architectures unless you mean loader as a synonym for linker. I'm thinking of the loader as the part of the executable file header that tells the operating system how to open and execute your compiled software.

I agree that reading the Wikipedia articles will probably impart more information than you're looking for. As to where they come into development ... generally they are beyond the control of the project, and are part of the selection of the operating system and the development package you choose to use. It's very rare that you would use (for example) MSVC but want to run a GCC based linker ... might not even be possible. The ONLY place I've ever used a non-standard linker was at IBM when we were using development copies.

If you have more particular, specific questions about these topics, I think you'll find a much better response.
Computers basicly work with binary numbers.  

People speak their native languages. 

Do, programming languages are for communication between people and computers.  

If you say: Add 2 and 3 and then substract 1 from it, I doubt that computer would understand anything (maybe in some programming language it would).

So, you need to translate your source code into a format that computer understands, so you need a compiler, which translates a programming language to co called object code. 
But object code is not yet the language a computer understands and executes directly. So it needs a linker which will make an executable file that containts instructions in so called machine language; a machine language is a set of operations coded into binary numbers which processor understands. All binary instructions have its structure and its published by a processor manufacturers. You can look for it on say Intel's site and see how do they look like.