or any other sized paper in a rectangle shape.
Fold your paper in half.
Sharp the edge with your nail.
Open the paper.
Now you have a very visible line sharing the paper in 2 long rectangles.
Step 1: Just begin with a simple sheet
Very simple, don't need so many explanations.
Do it for both top half sides.
Fold it over the line formed by the 2 top half parts you folded in the previous step.
Do the same for the top left side the way they get both symmetrical in the center line
The central triangle will hold top left and right corners together.
Fold your project in the central line the way right attack border and left attack border gets together.
Now Attack border will touch the central line completely.
Do the same you did previous step to the left attack border.