I am putting together the 41097 hot air balloon with my daughter and there is a red piece that shows a rod should go through however the rod will not go through no matter what we do. There seems to be a stop inside the red piece.
In step 1, you put the red joiner on the axle. In step 2, there is a smaller axle that gets put in the other end. The only clue is that each step shows what parts are needed, so you can see that there is a little axle there that needs to be incorporated.