Mrs. Puff wants you to find the 11 Boat Wheels hidden in the level for a Golden Spatula. Below is a guide from IGN on the locations of all Boat Wheels:
https://www.ign.com/wikis/spongebob-squarepants-battle-for-b...Once you've found all the Boat Wheels, you'll have to go back to Mrs. Puff (as SpongeBob, not as Sandy) to turn in the quest and get the Spatula.