this basically means you wanna make 3ds homebrew games. you need to learn programming in C first, if its too hard, ask someone else. if youre good though, check out devkitPro.

theres a chance C++ can be used instead of C, but i haven't tried it. other languages can't be used though, Mono still hasnt been ported, ruling out C#, and you have to wait a long time for a python interpreter.