You put your hand in, put the villain's hand in, enter the board. Hit evaluate. You input hands by clicking the little buttons to left (player1, player2, etc.).
I entered JJ vs. T7c on board of Ac2cJd. The set's equity to see the river is 75% vs. 25%. I entered Qs as the turn blank, hit evaluate again and the set's equity is up to 77%.
It took me like 20 seconds. So, you def might better want to start fiddling 'round with your PokerStove.