http://troy.spunak.com/TAPsDoc/html/index.html
Here is an example of .cpp and .h files that someone has written and made as a library.
How do I gain access to his functions and classes (Which directory do I place them in after downloading, and if I have to compile them?
How do I compile them?)?
Do I have to create a main function and run my code or does the library come with a
main function and I use the one provided?
A library is a reusable module that is used precompiled in particular system configurations.
How you use a library depends on your particular development environment, but with some versions of C++ you tell the linker where the library is (*.dll or *.lib, say) and tell it to incorporate the library in your executable (static linking) or use it as it needs (dynamic linking).
To use a particular library, the library designer may have included an IDE project file or a makefile so that you can build the library from source. Or, they might just provide the library as a binary. In either case, they might provide instructions on using the library, or show some examples. Actually, this one does:
http://troy.spunak.com/TAPsDoc/html/ex_c_d_r__fns_8cpp-example.html
Hope this helps.