Drill/solder holes in the tub. It will depend on your location as to how many holes you will need.
Attach a UTH that is about 1/3rd of the tub. The UTH MUST be regulated by a thermostat.
Place a hide on each side, and a water dish.
If you're using an accurite, you can drill a hole near the unit and have the excess cord outside of the tub. Drill a hole on the hot side so you can push through the probe to place over your UTH.