How the heck do you setup MAMEPlus Custom Buttons?

Seriously… I feel like a noob I’m so stumped.

Well after pressing every key on the keyboard, I finally figued it out. Seems 1-6 will assign buttons in the Custom Buttons menu. Which makes no sense to me whatsoever, why doesn’t it just take in the buttons as you’ve assigned them to your keyboard or gamepad. Anways I got it working…