[Scripting Question] Help adding Move Relearner to the Party Screen

[Samusnotmetroid]

So I found this
https://www.pokecommunity.com/showthread.php?t=407245

and this person has added the move relearner to their party screen so that it's accessible at all time and I would like to add this to my game but I'm having trouble adding it because the person who made the original post didn't specify where to put the scripts the and the call scripts.
I managed to add in the command in the UI of the party select screen but it doesn't do anything as I don't know where to put the call to the script.
When I try to put the call to the script in UI_Party, I get this error:
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Exception: NameError
Message: undefined local variable or method `cmbTeach' for #<PokemonPartyScreen>

Backtrace:
274:UI_Party:1317:in `block in pbPokemonScreen'
274:UI_Party:1202:in `loop'
274:UI_Party:1202:in `pbPokemonScreen'
270:UI_PauseMenu:182:in `block (2 levels) in pbStartPokemonMenu'
080:MessageConfig:562:in `pbFadeOutIn'
270:UI_PauseMenu:179:in `block in pbStartPokemonMenu'
270:UI_PauseMenu:147:in `loop'
270:UI_PauseMenu:147:in `pbStartPokemonMenu'
032: Scene_Map:102:in `call_menu'
032: Scene_Map:199:in `update'
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Please help, this would help my game immensely!