If the walls or the floor it's being attached to are uneven or out of level or plumb, then the tile work will be out of line by the same amount. A mortar bed application is a solid unit of sand and cement mix that allows you to level out floors or plumb up walls so you can install the tile on a flat, true surface. A mortar bed is a far superior application. You need to use a masonry bit on your drill. Make sure to triple check where you want the hole because should you misplace it, it will be difficult to reinstall the tile.
Ceramic tile reflects the room temperature and holds on to that temperature for a long time.
At times it can be cold. There are products out there that can be installed prior to tile installation that can warm up a floor. This is a HUGE misconception. Tile itself is water tolerant and does not decay in water. The glaze on a tile is waterproof.