PeeringDB Tutorial
The folks over at PeeringDB have a presentation on setting up an account and adding your network. https://docs.peeringdb.com/presentation/20190227-peeringdb-workshop-2-main.pdf
Internet Architecture
Interconnection, peering, Data centers. How the Internet works. IXPs, transit, and other topics. Routing and Control Planes such as BGP and OSPF protocols. RPKI and IP resources are also covered.