A trick is won by the highest trump card in it. If no trump is in the trick, the highest card of the suit led wins. The winner of the trick leads for the next one. If the bidder fails to make the bid, he pays each other player. If the bidder succeeds, he collects from all.
Nothing is gained by winning extra tricks over the bid.
The rate of settlement is usually one unit for each trick bid. Like nap, these are bids to win all five tricks. The difference is the payout for losing the bid. Wellington pays 10 if it loses and Blucher pays 20 for losing. Wellington overcalls nap and Blucher overcalls Wellington.