I bought that one. You have to do two things. 1) Take the wire leads off the pressure switch that the pot sits on and connect the ends together. It is some type of safety and will cut off the flame when you do not want it to. 2) If you are doing 5 gallon batches you will have to fill it to approximately 1.5 inches of the top so you need to watch the start of the boil very carefully. Start with a slow boil until some has boiled off or the bubbling liquid will go over the side even after the foam has subsided.
I got mine about 1 1/2 years ago during the winter for $10 less. I think it was mis-priced though and it should have been $5 more than I paid.
Add: I now use the burner to heat my HLT and use 10 gallon pots.