Advice on folding cubes: having tried it, I don't recommend getting students to do it. First fold all the edges back so they will stay in place better later. Then follow the numbers. While the numbered tabs 1,2,3,4 go inside, the "edge" stays on the outside of the box. Also, the tabs are a snug fir, if you push them in they may bend, so I pull the top corner to get the tab to go completely home.Once the yellow and white sides are done all that remains is to put the yellow and white tabs 5,6 at the same time into their  slots, thus closing the blue lid. As the blue flap goes in, the red tab goes into it with a bit of shuffling. It's remarkably rigid once done.

There is a video available demonstrating folding a cube at www.keele.org.uk/cubes/