Hi Awesome,
The links were in my reply (post #2), in my sixth paragraph. I’ll copy that for you again here. I checked, and the links are working:
Different manufacturers will offer various cover choices to complete the component mattress (popular ones are spandex/viscose/rayon/polyester blends, or cotton/wool covers), and then over that you could place some sort of mattress protector with a waterproof membrane (polyurethane is popular). A few good references for mattress protectors are in post #89 here and this post here.
Phoenix