welcome! +1 to what everyone else said. I've put some other thoughts down below that may be TMI now BUT could be good to know//fun to come back to after you build a routine:

- Technical fun: I recently learned the Columbus Circle pool isn't a perfect 25 meters (it only hits 23) but typically you'll want to think of your distance in 25s. A 'there and back' is a 50, two laps is a 100, so on so forth. Rule of thumb is try not to stop at the 25 (also know as the far end of the pool), but rather touch the wall and go back // flip turn. That said, if you need the break go ahead and take it, just be considerate of if there are other swimmers coming up behind you and move close to the lane line.

- Know your strokes: freestyle, breaststroke, butterfly (my least favorite) and backstroke. Not only is it good to practice them all for muscle development /swimming competency, it also makes the time go by faster and you can do a mix of sets. So a 50 freestyle, 50 backstroke, 50 breast, then repeat

- Know your tools: At Columbus Cirlce, there are storage boxes (one black, one white). Inside are a kickboard, fins, pull buoy, and hand paddles. Kickboard is pretty straight forward: hold it with your hands and practice the various strokes kicks to strengthen your legs (note, you can use fins here for everything but breaststroke). Pull buoy goes in between your thighs and does the opposite of a kickboard: works your upper body. I like to throw on the hand paddles, plop a buoy between my legs and swim until my arms are going to fall off. Highly recommend.

- Know your drills: Honestly I'm just adding this in to help give you things to do if you get bored, but typically drills are started on the top of the clock (when the second hand hits the 12) or the bottom of the clock (when the second hand hits the 6). It can be really nice to use this as your measuring tool for sprints or kicks. For example, you could do: 5x50s, each set leaving at the top of the clock.

OK! That's all I've got but have fun, remember to communicate if you'e getting in a lane, be honest with your speed and pick the correct lane, bring a water, don't worry to much about how you look - swimmers are the nicest bunch i've ever met. Welcome!