Yes, you have to respond each and every time the puppy rings the bell. Even when you KNOW she's only ringing them to play, or because she wants to go outside to play. She will only work out the cause/effect thing if you respond every single time.
Put another way, you can only start to be selective about which instances you answer the bell once you're certain that the puppy understands about toilet training - ie. that she must potty outside every single time. And that won't be for several months.
Does that make sense to you? Bell training is NOT housetraining. Housetraining, as in the full understanding by the puppy of pottying outside only AND holding on if the door doesn't open when required, is something that takes several months to master - going out with the dog, praising wildly the successes, and eliminating as far as possible any opportunities for her to get it wrong. All belltraining does is give the dog a means of communicating to you her need/wish to go outside. That's very useful! But the need/wish is not necessarily going to be potty related. Nonetheless, you must still respond every time up until the dog is housetrained (because if you only respond sometimes, she'll only ring it sometimes).
If you think she's going to play with it excessively at first, I'd suggest hanging it at a height that she has to make a bit of effort to reach. That won't 100% solve the problem of her ringing it just because she's playing with it (as opposed to wanting to go out to play or to potty), but it will probably cut down on the length of time she plays just for the sake of it.
