If the ceiling is plaster, the popcorn finish is covering a lot of cracks, patches, and bumps. I do not recomend removing the finish. If the house has a drywall ceiling it is a fairly easy job. The scaffolding is your biggest hurdle. You can remove the finish by covering the floor with dropcloths and plastic over them. Get the disposable masks to protect your mouth and nose, so you do not inhale the dust. Get a wide scraper and gently scrape away. You will have to do a lot of scraping. Then pick up the plastic and dispose of them, with most of the mess. Then you will have to repair the ceiling, prime, and paint.