Finally passed this level!!

Connect 4 bubbles = vertical power bubble

Connect 8 bubbles = horizontal power bubble

Connect 12 bubbles = flower power bubble

Connect 16 bubbles = X power bubble

If you do not have enough of the same color to create desired power bubble = you can make a chain of another color, and connect with a rainbow bubble to your desired color. Just make sure you are connecting the correct amount of bubbles.