I recommend using stiffer paper for this model. I've had especially good results with foil paper. For the model shown at the beginning of the video I used some foil-paper-foil sandwiches, which is usually a pain to work with. But you don't need to make many creases, and invert almost none of them, so it's an easy enough project for that kind of paper.
[old] 6-pointed Star Box (Robin Glynn): Instructions