Check that the frames of both shoes are contacting the large anchor pin on top. Next, use your thumb to push the parking brake strut rod against the anit-rattle spring. It should move at least 1/8". If either of those are not happening, the parking brake cable is not fully released.
Be sure you have the correct shoes in the right places. Short lining goes toward the front of the car, longer lining toward the rear. If two long linings are on the same side, the drum won't fit over them.