Don’t use standard PVA, it’s not a suitable tile primer & remains water soluble. Tiling isn't rocket science but there are many things that can catch out the inexperienced & I would advise you read both the Tiling Sticky (trazor's link) & Tiling Forum Archive posts before doing any more work or buying materials, it could prevent you making disastrous & potentially expensive mistakes. It’s also important to use only quality trade tilling materials of the correct type for your tiles & tile base; cheapo own brand & DIY stuff is mostly crap.