Add commands to System Drop Down Menu

I have several printers set up with Octoprint. When I did the first one I put commands to activate the GPIO pin of the Raspberry Pi in a the Systems drop down menu of Octoprint. Now... several years later I have added another printer. I can't remember how in the world I added the commands! I want to change some verbiage and add a command... but, I can't remember how I did it. Sure hope someone can help. I have tried finding the config.yaml file (after some online research) thinking this is how I did it. Have tried researching without much sucess.
Thanks in advance!

'System Commands':

I understand the process of to modify the drop down menu. where I am having the problem is finding the file on my Pi. I have gone to the proper directory (or at least what I think is right) but, can't find the config.yaml file.

That's also at the top of the page - ~/.octoprint/config.yaml

Found it! Problem fixed