Once you have access to the Locker Room, you'll need to keep an eye out for Jose. For a price, he'll help you clear out the locker room, so you have enough space to start growing mushrooms. The objective is to clear out all of the boxes except for one row on the floor. Once you have at least one box alone on the floor with none on top of it, you can start growing mushrooms. To start growing: buy a Grow Kit in the shop, tap one of your stand-alone boxes, tap the mushroom grow kit to plant them and then add water.