I'd agree that thinset mortar is the way to go. I was lucky enough to enjoy an extensive tile laying class before attempting any projects and thinset was the recommended product to use. A MUST, though to keep your sanity is to have a mixer tool on the end of a heavy duty drill to help you mix the mortar to a "peanut butter consistency." Good luck and have fun! Tiling has been my favorite project so far in our old home renovation.