Tacobell's on the right track, but this also has a good explanation. The decomps are harder to get started with, but the advantages of working with buildable code are worth putting in the extra effort. The simple modifications thread is full of little things that would be difficult to do in binary, but are simple in the decomps.
Most binary tools are useless or pointless with the decomp; all you need is some way to edit code (e.g. something like Visual Studio Code or Notepad++), porymap to edit maps, and maybe poryscript to make script editing easier. With the decomps you edit code and then compile it to build a modified ROM, instead of editing a ROM with tools. For example: rather than using a trainer editor to change a trainer's Pokemon, you'd open up trainer_parties.h, change whatever you want and then compile the ROM to see your changes in action.i see but i don't understand it fully. do i just delete my all tools, or do I keep the ones tht are used for heavy building ? can u explain a little more.
i would be very happy