Align aluminium extrusions as seen in the picture. 2 x M8 socket cap screws for top corners of the X frame. Do not full tighten them yet. Just to keep the frame in shape. (Do not forget to insert the T-Nuts before tightening M8)

2 x T-Nuts for every corner.

Black metal L brackets for each corner.

2 x M6 socket cap screws for each corner.

Insert 2 x T-Nuts to the top extrusion as seen in the picture in order to be able to mount the spool holder later.

Put your Z frame on a flat surface like glass or marble and then tighten the screws.