All I did with my 2 year old and toddler bed... was tell him he needed to sleep and lay down at various times during the day (which weren't naptime) the night before, the morning off during lunch etc... gave him a waring in 5 minutes we are going to take a nap etc...
I only went back to the room once.. and that's it...
I don't recommend going in several times... go in once after you've already laid him down...
Then if he's still awake around the time he usually gets up let him out...
Is he new to his toddler bed... It may take a little while for him to get used to...
I would also talk to him in the morning about your activities for the day... One of them will be nap... so then tell him how when it's naptime he is going to lay down and rest... If he wants to be strong like daddy, then he needs to rest... explain to him in toddler words why he needs to sleep and how you will lay him down and will not go in again... He can only get up to go potty... etc...
You may have already tried this...