Coding in C++ & In Need of Help

I'm in the process of making my own ( and my first ) mod menu for MW2 in C++ . I already have all of the coding inserted into the file ( correctly ) , I just need some help on what to do next. Do i just save the file and inject into the game or am I missing something vital? Thanks (:

I know I have to change the file into CFG, anything after?

what have dvars to do with c++? o: