rockinghorsedemon, further to DollysMom's comments about the thermostat, the thermostat comes with a temperature probe. This probe must be fastened directly on the glass of your viv - placed in the center of the uth. Setup should look like this: uth, viv floor, thermostat probe, substrate. You can use a hot glue gun or aquarium grade silicon to attach the probe to the floor.
The uth plugs into the thermostat and the thermostat into the wall. You set the themostat to given temp - it will cut power to the uth when the desire temp is reached and will turn uth back on when temp gets too low. The thermostat has a temp readout on it, you need to monitor this initially to make sure the temp does not get too high. I set my hydrofarm to 84, this keeps the temp between about 83 and 89.
As DollysMom indicated, using a separate digital thermometer (with probe - fastened next to thermostat probe) to confirm temps is a good idea. That said, I have found that the two hydro farm's I've been using for the last number of years are accurate enough and have stopped using a second thermometer.
While you are waiting for the thermostat to arrive, you need to get the temperature of the viv floor directly above the uth. If it is much above 87-89F, I would unplug it and do without for the meantime. I wouldn't feed though, until you have the uth properly set up.
Here is a link to the unit:
http://www.amazon.com/Hydrofarm-MTP...UTF8&qid=1428412326&sr=8-2&keywords=hydrofarm