McDonald v Chicago is the followup to Heller where the Supreme Court ruled that the 2d Amendment applies to individual states:

McDonald v. City of Chicago - Wikipedia, the free encyclopedia

Since you like John Grisham you might also check out books by Scott Turow. And, for pure amusement, watch episodes of Perry Mason on Youtube.

You can find explanations of legal terms by googling them. Many will come up on Wikipedia which you can use as a starting point for further research.

You can enter the minds of appellate court judges and examine the reasoning behind their decisions by looking up cases on Google Scholar and reading the complete decisions.

You can find the Heller and McDonald decisions there.

I have always had a fascination with the law and have learned quite a bit about it in my lifetime.