Create shortcut in Numbers

Hi all

Is there a way to create shortcuts

I used to press "shift, control, option, R" to AutoFill Right

"shift, control, option, L" to AutoFill Left

"shift, control, option, D" to AutoFill Down

I've tried Automator

Looked where I used to create them under Keyboard

Nothing seems to be available

I don't now how to do scripts

My previous computer was burned in a fire so not happy with Apple changing things to make them harder

Thanks for any help