I know at one point (in the 2000s, when ProvideX swung between the Sage and Best Software brands) there were classes to learn the language, an intro to Nomads and an Advanced Nomads course, as well as some OOP introduction.
I even found some old Sage & Best training / tutorials Word docs in my archives
An awful lot of things have changed since, but they would probably be still relevant for the most part
However I guess these docs (or up-to-date versions of them) are only available if you purchase some kind of training class with the experts
You need to check with your distributor if they offer this type of service, and if not, ask the PxPlus folks.