just a word of warning, my DD and DS hated being told they needed to go to the toilet/potty every hour, I couldn't imagine asking them to go every 20 mins. I ended up having 2 children that would totally refuse to go near the toilet which caused even more issues.

With my DD, I left her completely butt naked and everywhere she went I put a potty. I would place it on the ground and without making too much of an issue I would just say "the potty is here if you need to do wees" If she moved outside, the potty went with us and I would repeat "the potty is here..." It only took a day for her to start looking for the potty.

Good luck