In theory you can use this unit for icosahedron and dodecahedron geometries, but the dodecahedron was very unstable when I made it. I have a photo and that's about it. Maybe if you are using a paper with a lot of friction it might work (or glue would work too). On the other hand it was much easier to assemble. The icosahedral geometry pretty much requires pegs or clips while assembling!
To assemble you push the tab into a pocket on another module. It should go into the groove so that it is above the white part and beneath the coloured part (based on the picture here). The bridge part where the pinch mark is makes a good place to put a clip while assembling!
One last time to make sure you see it!! The dodecahedron is not stable! Make at your own risk, I have turned my pieces into an additional icosahedron model.