Rather than internet searches, which often seem to be cartoons, in my experience, actual written texts, such as slightly obsolete technical school books. Basic electrical circuit laws have not changed, KVL and KCL are the same, Ohms law is the same, and even the superposition scheme for network analysis is unchanged, although now it is called simulation and done by computers, which sometimes get confused.
@LowQCab That webpage is for a module that uses the part, not information about the XKR-412 specifically. Also, the diagram is labelled incorrectly. Internet searching is a skill of its own