A dryer bearing should be able to spin in your fingers, if there’s friction preventing the spin the bearing is no good and needs to be replaced.
First take the cover off the dryer to access the dryer bearing. Generally a 7/8 socket wrench will be used to remove the bearing mounting nut. Once removed take off the washer and slide the old bearing old bearing out. Next Slide the new bearing on, followed by the washer and the main mounting nut.