This first step is going to sound trivial. It isn't as trivial as it seems, and a shocking number of people manage to skip it.
Before you do anything else, you must understand WHY the tool or concept you're researching exists. If its purpose is not clear to you, you must clarify that first. Find a short overview of the tool or concept.
A general understanding of its purpose will help orient you as you attempt to understand/use it. The tool/concept has a purpose. If you can't articulate to another person what that purpose is (in a way that feels like it would be genuinely useful to YOU), there's a good chance you will struggle to use the tool effectively.