HELP-Runout micro switch - Ender 3 PRO

Hi, Tom’s

First, thanks for all your help on your YouTube channel.
I have some issues with the runout micro switch on Ender 3 PRO.
For some reason, I cannot upload the needed changes from the Marlin configuration to my printer.
I try everything without successת try not to go crazy (-:
Maybe can you send a good guide - step by step?