Help !!! teach me how to add cheat codes at R4 ultra

I bought mine at Bei jing . include 4 gb Micro sd. Can someone help me how to add cheat code at this type of machine?

http://cheats.gbatemp.net/ Download latest usrcheat.dat, overwrite.

Just overwrite the cheat.dat at system folder?I think nothing happen

It works. Download latest usrcheat.dat, delete your cheat.dat, and put the usrcheat.dat in _system_. Done.