Easy fitting :

Set your display body on a flat surface.
Assemble 2 modules on the vertical upper sides of a cross (report to illustration).
Assemble 2 more modules head to tail (to previous ones) on the lower sides of the cross to finish off 1st level.
Assemble this level on a plate so that the cross sides fit into the 4 vertical openings of the axis of the plate.
Stack level by level after assembling as previously, taking care that the upper sides of a cross fit between the vertical guides of the lower sides of an upper cross.
Assemble an upright plate on the top of the body.

NB : Mind to place 1 or 2 levels with a flat front side module (to stick a mirror with the 2 sides adhesives).