Answer I don't know but I have the same question. I can't get the basket inserted far enough to fit into the groove. Did you ever figure this out?
Answer So I googled around some more and found the answer. I put the baskets in boiling water for about 10 seconds and then they slipped on with just a little force.
Answer I didn't realize they had to be affixed to the pole! The fifth time I used them they fell off and were lost in the snow! There were certainly no directions...