I also recommend first fitting the pieces together without the wires to understand how it all fits together.
I'm a little confused about the previous poster's mention of the adapter plate - my memory was that the adaptor plate was for the wall mount, but I, as I said, I'm confused...
I found it easier to fit the stand to the BS5 vs. the BS5 to the stand. That is, I placed the BS5 face down on a carpeted floor, then twisted the stand on to it...
However, you are correct, it is not easy...
Stan