Cut along the solid lines, fold along the dotted lines. The ears and the gold ring things are meant to be folded back on themselves so that they’re colored on both sides (I’m seeing a lot of people who don’t get this! It’s somewhat important!). See the images in the gallery if you’re confused. I didn’t add the tail to mine because I didn’t glue the back closed, but basically cut along the solid line on the tab on the back part of the main body and insert the tab from the tail. If you make one of these, post it here, I’d like to see it!
I also added electronics to it (I am terrible at soldering; you have permission to laugh at the pictures of the circuit)! One servo for rotation of the entire papercraft, another servo and a rubber band for moving the ears up and down, and two photocells (one on each side) to sense light. I have it so that Cubey will turn either toward or away from light depending on what I set in the program. I tried adding remote control, but my IR receiver kinda broke somehow. Here are some videos of the other stuff, though.
And more on the channel. Image gallery in the full post.