HIGH DETAIL for AR on r4 wood?

I have been trying to get AR on my r4 for the LONGEST TIME.Wood R4 Kernel V1.23
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I have that version of it on my micro sd card right now, i've checked my _rpg thing and there is no cheat folder in there whatsoever, i've created a cheat folder there and it didn't work, I AM using Action Replay Code Manager, AND Cheat Code Editor, I enabled cheats on the game im trying to use it for, I made the file named usrcheat, when i name it do i have to put .dat at the end even though it is already a .dat file or something HELP PLEASE :(((Btw im trying to do this for mario kart, and pokemon heart gold