Nathan lawrence

I have an unit audio file by cnc asset extractor (extract to wav). i dub it to my language and rename like the original file (Not finish yet.). Now, i want to make a mod that replace the orignal audio (unit, eva, some movie audio, etc) but i don't know how to make it. some tutorial that i read it hard to understand because i don't what should i do next. It will be pleasure if you guy can tell me how to do it step-by-step. Ps.Sorry for my english skill