Potty training

Di

Anyone is potty training right now my son is nearly 3 and now I'm starting potty training before he starts school.what I am doing is that during the day I left him with pants and when I go out I changed him a nappy and took the potty with us but he pee in the nappy most of the time only few times ask for the potty to pee when out and when home he pees in the toilet what can I do should I leave him always with pants even when we out?share your experience thanks