07-10-2013 07:10 PM
Is this a hardwood plywood like oak or just construction grade plywood. You're going to need to clean the surface, sand, and finish it. Hardwood plywoods have a very thin veneer and it's easy to sand through them, so you'll need to be very careful. On the bright side, they only need to be sanded to about 100-150 grit. There's no need to get them super smooth.
Then stain and topcoat like a hardwood flooring.