Hacking can someone explain cheats to me?

[daiuf]

ok three questions coming your way:
1).generally,how do cheats work?
2).when i download the new cheats there are so many .DATs which one do i use?
3).may have something to do with question 2, when i put in a few cheat files i cant use any new cheats why?

more info: i have r4, normal AND ysmenu.

 

[elixirdream]

for yasumenu = usrcheat.dat

for normal = cheat.dat (forget about using it and google yourself why official firmware doesn't display cheats yourself)