No house, no book. The pool holds every dollar deposited and pays it back to whoever holds the winning side.
One USDC mints one Yes and one No token. Holding both leaves you flat.
Sell the side you disagree with. The price you get is the market's implied probability.
At expiry the resolver writes the BTC/USD price on chain. Above the strike, Yes wins.
The winning token burns for exactly $1.00. The losing token is worth nothing.