What's the right age to start toilet training? How does it work for boys? Do you teach them to stand to pee or sit down first?

I tried to potty train my boy when he was 1.5 years old and he was not ready at all. Thus, I delay until he turned 2 years old and the transition is a breeze. What I did for boy potty training include: - Borrow story books on potty training very often for him to understand why do we need to use potty/toilet - During the initial start, I let him diaperless (you can buy training pant too) and bring him to potty every 1-2 hours. After 1 to 2 weeks, he understands how to use potty and can control his pee better. - For poo, during the start he refused to poop in potty but in diaper. I showed him how dirty is his butt if he poop in diaper. After few times of talking, he finally willing to poop in toilet/potty - if there is any accident happen, do not scream/shout at him as this will cause his confident level to decrease. I just tell him, it is okay, accidents do happen some times. Next time you can tell mummy/go to toilet earlier when you feel the urge to pee. For boy, during the start you can let him sit in potty for pee. After he can control pee and master the use of potty, you can let him pee in standing position. I tried to switch between using potty and toilet seat for my boy so he get familiar with both and so far he has no problem in using public toilet too.