Step 4: Sew (option)
Also you can sew around cushions, but, not necessary. I did it, but I recommend it not.
All you have to do is cut holes on leather, and glue it for rubber sole.
But watch out, first add leather stripes and glue them from the inside to cardboard..
First version of sandals had no cushions, and no threads.
You can do it with no cushions, same instructions.