To bring your ingredients down you must set off the cannons at the bottom. You are given one ingredient on the board to start and 2 frozen striped candies in the upper right and left to help zip through the sides. Try to make vertical striped candies to shoot through the columns and if you can pull off a color bomb, mix it with any striped candy and you are all set.
All Candy Crushers that are stuck on Candy Crush Level 371 should have a look at this helpful video:
Patricia Frederick’s Tips for Candy Crush Level 371
Vertically striped candy matches are key here since there’s no room between the pizzas to work with. A striped/color bomb combo is very helpful. Remember, when the board clears, the ingredient has to be sitting on a cleared pizza top or it won’t leave the board and you have to clear another one.