Spades are always trump, and your bid is a promise.
A partnership game built on a promise. You say how many tricks you will take, and both halves of missing it hurt.
A 52-card deck, thirteen cards each for four players in two partnerships. Aces are high. Spades are always trump — there is no auction for it.
After looking at your hand, each player in turn bids the number of tricks they expect to take. The partnership's contract is the two bids added together.
Nil is a bid of zero: a promise to take no tricks at all, scored separately and worth a large bonus if it holds and an equal penalty if it does not. Blind nil is the same bid made before looking at your cards, for double.
The player to the dealer's left leads, and spades may not be led until a spade has been played on some earlier trick. Follow suit if you can, otherwise play anything. Highest spade wins, or the highest card of the suit led.
Make the contract and score 10 per trick bid. Fall short and lose 10 per trick bid — the whole contract, not the difference.
Each trick above the contract scores 1 point and also counts as a bag. Accumulate ten bags and 100 points are deducted. That is what stops partnerships underbidding for safety, and it is the part new players forget until it costs them the game.
Game is 500 points.