How do do i get the drums off from the rear brakes of a1998 chevy astro?

DO NOT HIT THEM WITH A HAMMER!!! Go to your local parts store and rent/borrow a Drum puller. It looks like a big puller used for Pulleys/steering wheels etc... If you hit them with a hammer you risk knocking chunks of metal out of the rim of the drum. Then you will need new drums. Reach inside the drum through the opening in the back plate and retract the shoes fully and then use the puller if they are still stuck on there. Dont know what I am talking about? If so, you have no business working on brakes. Good luck!