Step 1: What You Need
As far as the paper, I used grey origami paper. A six inch square makes 4 corners (1.5" wide). Any paper would work, newspaper might look cool. Also feel free to use bigger or smaller squares to change the size of the product. How to make a square is here: https://www.instructables.com/id/Make-a-rectangle-paper-to-a-square-paper/.
Step 2: Fold Step 1
Step 3: Fold Step 2
Step 4: Fold Step 3
Step 5: Cut, Form, Tape
As you fold each square, you will only need the creases you have already made, and they are all in the right direction already. Fold the left and right sides in to the middle, and then the top and bottom, so that the corners stick up/out. Then flatten, so that the 4 corner meet in the middle. See the pictures for help. Sorry they are blurry, but I think you can still see what's going on just fine.
Put a piece of tape on top to keep the corners together. Make a bubble of tape and put it on top, so you can stick it to the wall.
Step 6: Place
Step 7: Art
Just a note about my picture. The drawings I have inside these are pretty straightforward, just a little time consuming. I found images I liked online, and then used my laptop as a lightbox to trace them. Just turn up the brightness, open the screen all the way, put your paper on top, and trace. Then add some shading. As for the text, you can find tons of cool fonts just by googling 'font'. Most sites let you preview a word, and this can be traced too. If you don't have art to put in your corners, make some!