Heat will help you work out any wrinkles in the cover, but be very careful if you are using a heat gun. It won’t take much to overheat the vinyl and melt it. If you are going to use a heat gun, one way to prevent melting the vinyl is to put your hand in the line of fire, so to speak. Your hand will let you know right away if you are applying too much heat. You are better off using a hair dryer as they get the job done, but don't get nearly as hot. That completes the cushion for now; there are a few more steps, but these can't be done until the cushion and backrest are bolted back together.