Look out from the playground to the buoy, to the west of the swimming area. That is the mirror boat (sans mirror). The shopping carts are just to the east and a hair north of the boat. If you continue east, you will pick up the snorkel trail. Good luck.
When I first get a camera, I dump it in a bucket of water to make sure that nothing leaks. Make sure the O ring is lubed. But not much a drop of lube goes a long way. Make sure there is NOTHING on the o-ring. A grain of sand may cause it to leak. If it's a camera with a housing, put it together at home. The A/C in the car is cool enough that putting the camera in the housing at the bridge may lead to condensation. I save those little moisture packs from vitamin bottles for my camera.
Oh.. And put some sort of ID on the camera, name, phone number, email, etc.. Some people (such as myself) put a label on the interior of the housing. Others take a photo of your contact info as the first photo.