Brick + Beam Detroit

Hi Vicki, The best way to begin is by using a heat gun to remove the layers of paint, if you are lucky, the original varnish will still be on the door and that will bubble up and help the paint come off easier with the heat. If the heat gun does not work it will be multiple layers of removal using a paint stripper like CitrusStrip which works best of the readily available strippers. I personally like to leave the CitrusStrip on overnight while covered in plastic wrap to keep it from drying out. eventually, when you get to raw wood you'll be able to sand and refinish.