These instructions are to add an arm onto a the construction:

Layout the pieces:

First the scissor joint between the arms:

Place a pivot pin through one of the washers:

Place the 2 bushings on next:

Place the loose arm on over the bushings:

Place this assembly through the other arm making sure the second bushing doesn't fall off:

Place the second washer over the end of the installed pivot pin:

Place the second pivot pin through the whole scissor joint:

Press the pivot pins together firmly to hold the scissor joint together:

Now the arm/hub joint:

Place one of the hub tabs into the slot in the hub and slide it to either side of the slot:

Place the other hub tab into the slot in the hub and slide it to the opposite side of the slot:

Place the tab spacer into the slot in the hub and slide it all the way onto the hub between the tabs:

This will keep the hub tabs form slipping off the hub:

Place the bushing into the hole in the arm:

Place the end of the arm between the hub tabs being careful that the bushing doesn't fall out:

Place the hub pin with a full head through both hub tabs (and the bushing & arm),

it should be perpendicular to the plane of the hub:

Place the other hub pin (with a partial head) through from the opposite side (where the hub has a flat edge),

it should be in the plane of the hub with the missing part of the head adjacent to the hub:

Press the hub pins together firmly to hold the arm/hub joint together:

What you end up with: