Admin Panel Addon

[Daniel Hood]

I'm working on an addon for the users group page. I want to edit groups to be able to give them another field. I am having major trouble finding needed files in this system. Could someone please tell me where to go about this? Also I tried yesterday to add another page to the admin panel and I couldn't for the life of me figure out how.

I'm no rookie coder but having trouble learning the structure of this system.