The rules are simple: each player finds a stick, and then you all drop your sticks, at the same time, on the upstream side of the bridge (the side where the water is flowing from), and then you all run over to the other side to see whose stick comes through first. The bears all argued about what type of stick would be best - should it be short? Or long? Should it be heavy? Should it be straight? No-one could agree so they ended up with quite a mixture.
On their first try, all their sticks got jumbled together as they went under the bridge and when they came out the other side, no-one could tell whose stick was whose, and they all claimed that theirs was the first one through. That didn't work very well. It would have been a good idea to have painted the ends of the sticks, or stuck on stickers, so that the bears could recognise them again. But they didn't have anything like that with them.