Breakdown boxes into flat squares.  As designed, the largest piece necessary should be approximately 15"x15".  If desired vector designs from the files can be scaled and copied into a single file, so the necessary size of the cardboard may vary.

Open the xTool Creative Studio files and cut the structures.

Assemble the pieces of the structures.  Tabs added for connections can be folded back on themselves and glued to provide more surface for connections if needed, otherwise the cuts can be modified to remove the tabs.

Paint, color, and otherwise decorate as desired.  This is the fun part for young kids.