Start by tearing out a centre fold page or use any double page from a old comic book. The page should be the same size as an A4 page. So I traced an A4 page outline over the comic book page and cut around the outline.
Step 2: The folding
Place the page landscape and fold in half so have rectangle shape.
Step 3: Refolding
Unfold the page and fold the end of the page in half into the crease. Now do the same to the other side.and fold the whole page in half so you are left with a long rectangle.
Step 4: And fold some more.
Fold in half again this time from top to bottom.
Step 5: Cutting and trimming
Unfold the page again and you should be eight creased boxes. Place the paper vertically and cut into each crease on the left and right 2cm. Now fold the page closed from right to left and trim the ridge of the block at the bottom and cut a triangle in the the second block. I have added a picture to explain. cut along the red lines.
Step 6: Folding flaps
Fold over the the top and middle end of the flaps you have just cut and a a piece of tape to the bottom middle of your page to keep the page strong.
Step 7: More folding
fold the page in half from right from top to bottom, the in half again.
Step 8: The finishing
Fold in you the flaps on either side or tape them down and you are done!