Parents often want to know when to start potty training. Here is my answer:
Begin "training" when your child is verbal. Start by helping them learn the language they'll need, like "pee," "poo," "bum," "potty," "toilet," etc.
Somewhere in the middle of their second year, you can buy a potty and get some fun children's books about potty training.
Let them see you using the toilet (if you are like me, you have never had a minute alone in the washroom anyway!) and let them "play"/"imitate" you by either sitting on their potty or the toilet (with their pants still on is typical), or putting their dolls on it. This is still about "play," not "trying" to use the toilet.
Show them how to dress and undress so they can pull their pants down and up on their own. Show them how to wash and dry their hands at the sink. These areas should be kid-friendly, with step stools and easy-to-reach soap and towels.
Look for 2-3 hour periods of dryness and predictable bowel movements each day.
Body maturation and awareness comes in three stages: "I peed," "I am peeing," and "I have to pee." When they share "I peed" and "I am peeing," you can smile and say encouraging comments like, "Hey, you are really getting to know your body!"
Only when they get to the "I need to pee" stage, which means they now are able to hold their bladder and have a chance to actually plan to get to the potty, is it time to invite them to try to use the toilet or potty. This, in my opinion, is when active potty training takes place (somewhere around between 2 1/2 and 3 years of age) and it means having you child wear fast-to-pull-down track pants or leggings –- no zippers, belts, buckles or overalls, please.
Now you can invite them to try to do that pee (which they now know they are holding) on a potty! It's an invitation to try –- not a life sentence of sitting until something happens! They can sit and try, and when they want to get up, so be it. They can try anytime they like. The next time they announce, "I have to pee," ask, "Do you wanna try the potty?" If they say yes, say "Let's go," and then move quickly to the potty and get them on there quickly. They can't hold for long at this stage, so if they don't make it to the toilet, say, "That's okay, you're learning!" and stay positive.
When to stop training (You are being too forceful or are taking over the lead):
If they say NO. No means NO and you have to respect that. If they don't want to use a toilet, they may be ready physically, but not psychologically.
If they are holding or constipated, whatever you might be doing –- back off!
If they have many accidents and never even make an attempt to hold or get to the toilet.
If they don't go when they are on the potty, but then go immediately after being re-dressed.
If they hide to go.
Hope that gives you a good start!