Changing a toilet is really not the dirty and difficult job that you would imagine. Start by turning the water off using the valve that is located on the wall. Empty the tank by flushing the toilet and holding up the drain valve. Soak up the excess water with a sponge. Disconnect the water line and loosen the bolts that hold the toilet down. Cut through the caulk seal at the bottom of the toilet. Remove the toilet and the wax ring that is around the opening of the drain. Remove the wax ring and install a new one on the bottom of the new toilet with the plastic collar facing up. Pack plumbers putty into the slots of the flange to hold the base bolts upright. Lower the toilet so that the base bolts go through the holes in the toilet. Then press the toilet down so that the wax ring is compressed. Put a cover base over each nut followed by a washer and nut. If the bolt is pre-cut you can snap it off using pliers. Tighten the bolt down and put the cover over the bolt. The tank will have bolts coming out of the bottom of it that will match holes in the bowl. Put the tank down with the bolts going through the tank. Put the washer and nuts on and tighten them up. Install the toilet seat, connect the water line, and turn the water back on.