You show up. Well, first you check black out periods and make sure you are "safe" - ideally you call the front desk to make sure the pool is too crowded (I'm guessing few people do - people who have have reported the front desk often says 'huh?') If you have a car, you probably want to put on swimsuits in your hotel room and drive over. Otherwise, throw your swimsuits into a bag and catch Disney transportation over and change in a bathroom at the resort. Bring your blue DVC member card and your room key just in case the pool hopping police are out.
ETA: Of course, no hopping to the Y&BC pools or to the AKL pool. No hopping during blackout periods, no hopping if you aren't staying on points.
We did this when we were staying at OKW. We just showed up...but you did say you are going over Spring Break. There's often no pool hopping then...pools are too crowded.
But the OKW pool with the new slide is great! We love it.