It depends on if the toddler is ready to potty train but you can start introducing your toddler boy to the potty as early as age 18 months old.
If they're not interested in using the potty at 18 months old then you might have to back off and wait another 6 months to try again when they're 2 years old.
If your toddler still doesn't want to use the potty by age 3 then it's time to start forcing the issue of potty training.
Most toddlers though are fully potty trained by age 3 and some before age 3. All children are different and will potty train at different ages.