They just stopped. Once I realized that the pull ups they were taking off in the morning had been dry for a while, I had them sleep with no bottoms for a while, and when that was dry, we went to pjs without pull ups.
I had them use the potty when they brushed their teeth from the point they were potty trained, but I'm not sure that prepared them for anything. Their bodies just weren't ready and then they were. For my kids it happened when they were 3, for other kids in the family it happened later, it didn't seem to align with any other skills, or how early they day trained, or anything, their body just figured it out.