Hello, please let me start by saying that I am a total beginner with DIY projects. I'm trying a very small tile project for the first time. It's a 25"x50" fireplace hearth that will be flush with our hardwood floor. I started by removing the unwanted tile and discovered a 1/2 thick layer of mortar, which I removed as well. This revealed another layer of tile below. I also prefer to tile over this. But to have my new tile rest flush with the surrounding hardwood, I'm think I need to install 1/2" hardie board over the original tile.... First question: is this the correct way to do this? Second question: what is the best method to adhere it? Mortor? ... Once that is down, I feel good about the instructions for the tile install. Any advise is appreciated. Thank you!!