You and fellow players are dealt two cards each whilst the dealer is dealt one face up. If your first 2 cards add up to 21 (an Ace and a card valued 10), that's Blackjack! If they have any other total, decide whether you wish to 'draw' or 'stay'. You can continue to draw cards until you are happy with your hand.
Your goal is to draw cards that total 21, or come closer to 21 than the dealer without going over. The dealer and each player start with two cards. The dealer's first card faces up, the second faces down. Face cards each count as 10, Aces count as 1 or 11, all others count at face value.