- How to patch a ROM hack -

First of all, you will need something to patch with. You will either be patching a .ips or .ups file to a .gba/.nds in order for the game to be playable. LunarIPS and NUPS are the respective applications for ips and ups patching.

Lunar IPS: http://www.romhacking.net/utilities/240/
NUPS: http://www.romhacking.net/utilities/606/

Step 1: Open up Lunar IPS/NUPS
Step 2: Pick the ROM that the game patches to, and the patch
Step 3: Press patch