New Parts needed for this step:
There are two cranks shown, each flanked by a weight on each side.
As concerns this step, the weights and cranks are bidirectional.
Fully insert the weights into each crank.
Weights are adjustable. Though not critical in the model, they are very important in balancing the unit. If the weights are not installed far enough onto the crank, as in real life, they will strike the ground.