When you begin potty training your child you should do it on a day or a weekend when you're gonna be able to stay home all day and be able to focus your attention on the child and their potty training.
You should take your child to the potty every 20 minutes. Set a timer for 20 minutes and then take your child to the toilet and sit with them in the bathroom until the child potties in the toilet.
Be prepared for potty accidents in their pants and/or on the floor. If your child has an accident don't punish or scold them just tell them that it's okay and clean the mess up and tell them they'll do better next time.
When they do successfully use the potty then congratulate them and make a big deal about it.
Toddlers get a kick out of pleasing their parents.