Hi, thank you for your comment!
As for your question, unfortunately I don’t have a cut and dry answer for you because thats not really how the game is structured. Remember, PCS aren’t rolling to clear obstacles, they’re rolling to cast spells.
For example, let’s say one of the challenges is that the room has no gravity. One PC might try to use Druidic magic to grow vines that hold them to the ground, and they’d roll to see how successful they are. Another player might use the lack of gravity to their advantage and push themself off the walls to fly around the room, which wouldn’t necessarily require a roll at all. Bigger challenges like the ones in the final test will probably take a few different spells, unless one PC comes up with something particularly clever.
As a GM it’s up to you to decide what the win condition for each room is, and then the players succeed whenever they meet it. And honestly, even there I would encourage you to be flexible. Like, the room setup with the spider on page 7 came from a play test. In my mind the solution was to attack the spider/help the ghosts kill it, but my players sided with the spider and helped it get the ghosts. Not the ending I expected, but everything they did made sense and felt satisfying, so it counted as a win. (IMO this is true for all ttrpgs honestly! If you set up a puzzle and they find a totally different solution that feels cool, you can just make that be the solution!)
In that encounter it wasn’t like I kept track of how many times each PC succeeded on a roll and then when they hit a certain number it was over. They rolled for things like using magic to climb up the wall to get a better angle on it, or to communicate with the spider to see what its deal was. There’s no mechanic for HP, so when they attacked the ghosts I had to decide in the moment how many successful attack spells felt like enough.
TLDR it’s all vibes based, they succeed on a chamber when they’ve done enough for it to feel like a satisfying conclusion.