Hi!
Whenever you choose a Feature to make a Check attempt, you roll a number of dice equal to it's value. Then count all Passes and all Fails.
Example:
You need 2 Passes to clear an area.
You roll Prowess, which has a value of 5, so you roll 5 dice. You get 3 Passes, and two Fails = the room is cleared, that's for sure, since you got at least two Passes.
Now comes the Tally!
Passes: you two 5's and a 4; Fails: you got two 2's.
Start the Tally from the highest values: 5, 5, 4, 2, 2.
So it goes like this:
5: (Up your Features or choose new Items) x2.
4: (Decrease any Feature by one, or lose an item)
2: (Decrease any Feature by one) x2
And... see if you're still alive and/or found anything good :)