lol... starting from the pokémon-mini are we?
The device may look small but developing on it is nowhere easy... and yes, developing on PC is waaaay much easier believe me!
In the Team Pokémé times we used assemblers, the best assembler for PM is still PMAS by DarkFader.
Anyway check this post
to have an idea of the big picture, there's similar posts around the forum too... follow Wa post for the ASM approach
in that link but keep in mind that is not compatible with the C compiler.
For C you can read this post
first and if you're brave enough follow zoranc instructions of how to set it up