Grounding: give it the source
Reading a document you supplied is a safer job than recalling one.
A model summarising a document you pasted is doing a fundamentally more reliable job than a model recalling one. It can still misread, but the failure becomes misreading rather than invention, and misreading can be caught.
In practice: paste the source, ask it to answer only from that, allow the answer "not in the sources", and ask for the line it used. This one habit removes most invented facts.
Find your way around
Learn it in the course, copy it from a playbook, see it work in a case study.