First make sure the plywood is level, sand any areas that are rough. When plywood is smooth sweep and clean, let dry completely.Use damp mop do not overly wet plywood. Let dry completely. Paint with high grade paint, two coats, letting each coat dry between coats. The beauty of paint is that you can choose color, design, stencils, free hand drawing, doing whatever makes you happy. Finish with a good quality sealer of your choice. My personal choice is a marine grade simply because it hardens and protects from water damage. Two or more thin coats, again letting each coat completely before adding another coat. Your floor should remain beautiful for many years. Best of luck with your diy project.
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Hi Nan! Here are some helpful instructions. My best to you! Have a Happy New Year!!