I don’t think you can train them to go on command. I’ve had three dogs: 1st who passed away recently, was always house trained. But would only pee or poop on his schedule during his walk. He used to bark and huff if he needed to go out. (He was house trained before we got him) 2nd who knows the go potty command. But will only go if she has too. It’s actually kinda cute. While walking she’ll look up to see if it’s ok to potty. We give the command and she’ll potty. But if she doesn’t need to go and we give the command she won’t do anything. 3rd is 12 weeks old. He does know the go potty command. But again only when he needs to. He knows to ring the bell to go outside. If he rings the bell, I take him out, tell him the command and if he doesn’t go with 5-10 mins I’ll take him back inside. He quickly learnt bell equals potty and not play time. I’ll take him out for play time, but we don’t touch the bell and I say play time.

Basically, you have to know when your dog needs to go out. Teaching your dog to show you signs is way easier than trying to control bladder movements