1. Launch the Cards 21 game on your mobile device.

2. You start the game with 3 lives.

3. You will see four columns or platforms on the screen where you can place cards.

4. The goal is to place cards in each column so that the total value of the cards adds up to exactly 21.

5. You are allowed to use a maximum of 5 cards in a single column to reach the total of 21.

6. If the total in any column exceeds 21, you lose a life.

7. If you place 5 cards in a column and the total is not 21, you also lose a life.

8. When a column reaches exactly 21, the cards in that column are removed, and you score points.

9. Drag and drop cards from the deck to any of the four columns.

10. Think strategically about where to place each card to avoid going over 21 or using too many cards.

11. The game continues until all three lives are lost.

12. There is no time limit, so you can take your time planning each move.

13. Look out for bonus features that give you extra points or help you clear the board.

14. Try to score as many points as possible before losing all your lives.

15. Restart the game anytime to try beating your high score.