All you have to do is wet the stuff with a squirt bottle and then scrap with a putty knife or some such flat instrument. Very messy and the wallboard underneath will probably not have any texture at all (unlike your walls), but you can add some texture yourself or just leave it flat and paint. The only other problem you might have is that some of these "cottage cheese" ceilings have asbestos in them so I'd wear a mask and gloves. Good luck!