First, you need a rectangle of paper. You might need to cut or fold the paper in half so that the ratio of the breadth to the length is 1:7 ( the length can be longer, it doesn't matter)
Repeat on the opposite end. Now, take one of the folded ends and fold the two flaps to the middle ( see picture)
Fold in the two rectangular edges on the left and right ( see picture) i'm bad at explaining things.