This build had its challenges. As with the other toys that used a pulley system, the derrick was in continual danger of collapsing from the tension of the suspended load.
In order to get the boom to stay upright, I used some Candle Stick-Um to glue the beams in place. Stick-um is a mild adhesive, and can be completely removed afterwards (especially from flat surfaces like these construction pieces).
I'm sure the illustrator assumed that dowels inside the blocks would help them align perfectly for the tower. Perhaps -- if one dowel was long enough to run the length of it. But I didn't have that option, so the tower looks a little more teetery than it does in the instruction sheet.