This image

shows the arrangement and dimensions of a module from the end while this one

shows the general arrangement and indicates how the ends differ from one another. The slotted rail along the lower front of the module is used to support a black cloth valance during shows but also functions to locate the top of the back scene when modules are packed away

Modules fit together in permanent pairs with the "east" ends (here labelled "A") and the "west" ends (here labelled "B") together, then an end plate is bolted on using the same fixtures used to link the modules together when in use

to form a rigid box in transport and storage. The "A" ends do not require wing-nuts because of the captive nuts fitted at that end. (These images were taken in 2014 before location dowels were added to the standard.)

Corner modules, which have angled ends work the same way but have two end plates at each end labelled "E" and "F" ("B" and "C" plates are used for storage yard modules which don't have back scene boards and are much closer together).

Note that that scenery is carefully designed so that it does not collide with that of its mate!