Hi Ellen @ellenjones123 , nice to meet you! PHP Admin API is personally out of the realm of my expertise, but thankfully we have many knowledgeable admins around here that may be able to help you out.
I will say that we do have some e-learning courses available in beta right now that other new administrators have found useful. So far, we have lessons for an Introduction to the Admin Panel, Policies, and Authentication Methods, as well as a focused course series for training helpdesk support personnel. Unfortunately, I don’t think you would find it too useful for guidance creating your module, but if you or anyone in your organization is ever interested in participating, let me know and I can generate an access code for you.
Have an awesome day and welcome to the community!