Mine are bell trained but the younger one doesn't really get it yet. He waits until I ask him if he needs to go out and then he rings the bell....oh well he will figure it out eventually.
I trained them the same way, but I waited until time I knew they would have to go; after meals, first thing in the morning, etc. and then took them to the bell, rang it, said potty, and then we went out. We have a strict no playing until potty rule in my house (because the puppy can be a real pain about that) so we don't really have ringing except to potty.