The intent of this step wasn’t obvious. I got to the step where I stack the z-axis frame onto the y-axis frame before realizing that the aligning beam in this step was meant to leave an overhang for attaching to the y-axis. Maybe show a view from the other side of this step showing that the beam butts up against the end and doesn’t rest on top. It’s hard to see with the joining plate already in place.
The remaining joining plates work well as the object to lift the corner. If one isn’t enough to bend the frame back into the plane, then adding a second (or even third I guess) works well. My frame was flat after bending using two of the plates.
What felt pads are these?