Having made a first assembly, you now need to take bits apart, do what the instructions said in the first place and sort the joints out. The first thing you realize is that partial disassembly is just as complicated, if not more so, than building the thing in the first place.
Time to get the wiring sorted out, take them stupid springs off, and work out how to properly assemble that wrist rotator so that the wrist itself can move like it ought to.
At last! A mechanically complete robot arm!