Nap question

Soooo I know this might be a silly question but my LO sleeps very good at night time, but during the day he always naps on me (rocking) or in a swing.. Once in a awhile he'll fall asleep on his own when he's laying on a play mat, or dock a tot on the couch when I'm sitting with him. Now I'm trying to have him take all of his naps in the crib. But when I put him in (when I know he's tired and it's usually his nap time) he's gets more awake and wants to play..

Do I just let him lay there on his own to fall asleep? How long do I let him try to figure out it's nap time?? Or should I pick him up and play with him until he's tired again?