Choose a bingo room from the main lobby and you will be brought to the Card Selection screen for that room. Choose the number of bingo cards you would like to play and how many cherries you want to bet. Betting more cherries increases the payouts, unlocks the ability to get 4 bingos on one card, and increases the number of puzzle pieces that appear on each card. After setting your bet tap the Play button. (Note: You need to reach level 5 before you can change your bet)
Next you will have the opportunity to pay coins for some power ups. You can pay for Standard power ups like Bonus XP and Bonus Coin Tiles or you can pay more coins for extra-special power ups like Instant Bingo and free Double Daub! Or if you do not wish to use power ups you can just tap the Play button. Once you tap Play the cherries and coins you paid for the round are deducted and you are taken to your bingo round. Good Luck!
For more information on power ups please see "What are Powerups"?