IML: 1961 chrysler rear brakes

I just don't get it. I need to replace the brakes shoes on the rear of the car. So I jack her up put her on stands. Pull the wheels, take the pin out and unscrew the center nut.Thats it right theres nothing else to do. The wheel spins freely. I noticed it wasn't coming off so I used a drum puller. Now I used a impact wrench. It didn't take it off. Is there something here I am missing. I also tryed prying it off is that a good idea or not . How much pressure is enough and can i damage anything by doing this. Is there something or a step that I am not doing. What i don't understand is when you look in a repair book they have nothing on pulling the drum .Just how to install brakes its like the drum must fall off for you ? Until you remove the drum you cant do the brakes. so why is there nothing on it ?.Does the e-brake need to be off ?or does it matter ?why is it so hard to get off.I don't understand. Can someone give me some in site on this thank you Mark