Author of the package here. Joining 5 tables is not a problem.

The training does not necessarily require you to write the queries by hand. A trick that we've seen people do is to just train with DDL statements and then ask "leading" questions if it can't answer on the first try.

I've been using the package myself for about 6 months and while I haven't forgotten SQL, what I have forgotten are the fully qualified table names and which tables live in which schemas etc since I never have to think about that.