What are the unwritten rules of a community-center lap lane?

I joined my city recreation center because it has a pool five minutes from my house and an affordable monthly pass. I can swim, but I have never swum laps around strangers who seem to understand a complete transportation system that nobody explained.

The posted sign says “slow,” “medium” and “fast.” I chose slow. One person was moving steadily down the center of the lane, another joined and began circling, and I stood on the deck pretending to adjust my goggles while trying to determine whether I was supposed to ask permission.

When I finally entered, I waited at the wall to let the faster swimmer pass. She stopped too. We both said “go ahead” twice. Later I felt someone touch my foot and assumed it was an accident. At the next wall he passed me with the efficiency of a commuter changing trains. I realized the touch may have been a signal, but by then I had already made it awkward.

Nobody was rude. That almost made the uncertainty worse because there was no clear incident to learn from. I spent more attention on lane traffic than on swimming. After twenty minutes I left, even though the pool was the entire reason I joined.

I could ask the lifeguard, and I will. I would also like to know which customs are broadly useful: when to split a lane, when to circle, how to signal a pass and how long it is reasonable to rest at the wall. I am not trying to claim space that belongs to regular swimmers. I am trying to become a regular swimmer without causing a minor aquatic traffic jam.

What would you tell a beginner before the second visit?