norah, do you praise them every time you put them in bed? I have three families going (I know I'm addicted) and the first family I spent a lot of time praising them for going to sleep, they would get up, do something, be tired again, I'd put them to bed and praise them. The other two do not sleep on their own, but I did not work with them as much. It takes a little while but I think the point of this game is you're supposed to train them in a way, like kids. You put a kid to bed and they want water, potty, toys etc... but eventually after you say good boy/girl most their childhoods, they sleep on they're own lol

Just my opinion, hope its helpful.