I think there is/are retainers on the wheel studs (thin things that hold the
drum on...can be discarded after removal).
Once it comes off, you can knock out the blank behind the starwheel adj for
future use....guess you gotta buy a rubber plug at the parts place.
I got mine off without doing it, but am sure you could pry off the blank
behind the star wheel to get to it if needed....not sure which one per
wheel....if you take 'em both off a wheel, you just need to buy extra plugs
later.
When I put mine back on, I just adjusted the brakes tight as possible to
still get the hub on.
If you have much drum wear, am sure you are  gonna  have to pry the star
wheel adj blanks out to back off the shoes first....
The GM manual says they are knockouts.
Good luck
Pete/MS

Usually the only problems I have, is that the drum is rusted on,
in the center. Couple whacks with a heavy hammer usuall breaks
the rust loose.

Are you trying to get at the adjuster star? Not really needed,
unless the drums are badly ridged around the edge.