When you start training pants, you need at least 10 pairs. And if you've got more than one toilet, you would set up each toilet/potty set-up with the same equipment.
When choosing to move to training pants consider:
Looser waist fitting. The easier they are to pull up the faster independence is achieved.
Plain colours/limited choice. If they’re all plain/similar we can avoid tantrums around only wearing the favourite one.