Help New to modding wanting some advice

[DyingSpree]

Does anyone know how or if it is even possible to set up custom classes with things like only a balistic knife and being able to shoot a flame thrower from it by pressing right, or having custom killstreaks that are different to each team? if you could give me any advice i'm very interested in learning how to make my custom game ive been tweeking for a while into a full mod.

Thanks in advance