You train him by staying on top of things. Don't be good at it one day and don't work on it at all the next. You and him will pick up a routine. Both of my children were 1 and I would sit them on a potty a few times a day. or right before I know they were going to poop in their diaper I would put them on the potty. My son had a body clock. It was weird but he would poop everyday around the same time so I used that to my advantage and would put him on the potty we would sing nursery rythms, count, anything that would not make him bored. He started going on his own soon after, I can't take credit for that. I started a routine and he picked it up and ran with it. All children are different figure out what works for your son. Don't be afraid to try something new what you are trying isn't working.