you will need to get the ceiling tested for asbestos- the popcorn ceilings are noted for it. if its clear of asbestos, wet down the ceiling with a mister and start scraping it off. put a tarp under the area you are working on.
Carl...There are many videos and you might Google and take a look.
Hi Carl, We have scraped a few popcorn ceilings. Wear a mask for protection. Spray the ceiling with water we use one of those sprayers that you use in the yards for spraying weeds. Let the water sit for about 30-60 seconds then take a putty knife and start scraping. Its pretty easy to do its just time consuming and messy.