I'll describe the general procedure for adding a layer to the stack of jig & prop parts, step by step.
Here, the prop part has been cut out from what the rest of the layer part. The rectangular remnant forms the jig. The inner edges of this is carefully brushed with petroleum jelly (Vaseline), on both sides of the paper. Next, glue is applied to the end parts only of the already started stack:
Glue is always applied to the stack, not the part to be glued. This is to avoid making the slender prop parts even more flimsy from wet glue. (The two bottom layers of the stack are treated somewhat differently, as described in the instructions of the kit; here we are only concerned with the general idea.)
To keep the glued jig part from bulging ("lifting") from the stack, a thin line of glue is applied to the long edges of the stack.
After a while I discovered a better way, namely to sort of "edgecolour" the top of the stack with glue before pressing down the jig part. The "edgecolouring" is done so that a very thin line of glue is left on the top surface of the stack. The effect when a layer jig part is pressed on to this is somewhat like the binding of a paperback book or a simple tear-off notepad.
The stack with the glued jig part is placed between two glass panes (from cheap picture-postcard, clips-type frames). A hefty weight is then placed on the glass panes (with the frame backside as protection). I used between 2,5-5 kg (5-10 lbs) for this build.
Glue for the prop part is spread through the cut-out in the jig. Avoid smearing too much glue on the very edges of the jig. In spite of the petroleum jelly, some might adhere.
Stick a needle through the centre of the prop part and place it in the cut-out of the jig part. Alignment is almost automatic. And press down again:
After a while I learned to make these two operations in one go, which saves time. But making this prop is still a time-consuming process. Be prepared to do something else while each layer, or at least every second or third, is left alone to dry out for a while.
If parts of layers start to bulge, you have been trying to speed things up too much. Leave under pressure for some additional time.
When all layers have been glued, let the finished stack dry out completely overnight.
Leif