Buy a ticket-(note that there may be a time limit)

Entered the door-paid the ticket-took the lock-(for storing clothes)

Go into the locker room and look for the cupboard-(ask the staff if you have any questions, and don't go to the wrong door)

Change swimsuits-(slippers are generally not allowed in swimming pools)

Swimming in the pool-(you need to bring a swimming cap, and you may need a deep-water permit, just bring goggles)

Take a rest when you are tired of swimming-(there is no limit, you can float in the water or sit by the pool. If there is a lounge chair in the museum, you can lie down for a while and drink some water.

Finally, if you don't want to swim, go home. The process is the opposite.