3) Which ROM to get for a patch found on ? The important information can be found on the patch's site at the heading 'ROM / ISO Information'. To play the game, you have to patch these files using a patching tool such as Lunar IPS Patcher (IPS file patching) and Tsukuyomi (UPS file patching) Please note that these files are for FREE, while some creators accept donations, you can report to the game author if you caught someone sells. Pokemon ROM hacks are distributed in the file for GBC and GBA and xdelta for NDS.
There are several UPS patchers out there like - UPS Patcher - TsukuyomiUPS - NUPS - NUPS Mirror UPS patches allow you to expand the ROM without having to do use the dual patches method like StealthPatch, making it more efficient and easier to understand. As mentioned before UPS is a better format for patching files.