re: Need help, I’m retiling my bathroom

Strip down to the subfloor, then install Hardi board throughout. Thinset, tile, grout- done. You dont need to glue or thinset the Hardie down to the subfloor, just use a high quality thinset when installing the tile. Depending on the initial install, you may have a height difference from your hardwood (or other existing) floor to the new tile. Add a transition piece and you're good to go.