I’m quoting a tile job and need some ideas on how to treat the floors.The floor extends into two rooms and there are wood subfloors on one side of a door and concrete on the other they are the same hight I know I have to use cement board over the wood but in order to keep floors level I have to lay and fasten the cement board to the concrete floor correctly. There is vynle on the concrete. Any ideas on how to fasten to the concrete.