First, round up your supplies. You will need an old bed sheet or fabric large enough to cover the box spring of your bed, as well as the fabric for the skirt. You’ll have to do some measuring and figuring for just how much you need for the skirt itself.
I measured to 20 inches and snipped in about an inch and a half. Drop cloth will rip evenly. So rather than cutting everything at 20 inches, I could just add that snip and rip all the way down.