Step 1:
Fold the flap in half the long way.
Step 2:
Fold both edges in toward the middle so they meet at the center crease.
Step 3:
Fold two corners out at an angle of about 30 degrees.
The parts that stick out on the sides will be the shirt sleeves, so use that to help visualize where they should go.
Step 4:
Fold the bottom edge up about ¼ of an inch or 1 cm. This will be the shirt collar, so keep that in mind to judge how wide it should be.
Step 5:
Turn over and fold the corners of the collar in toward the center to form the neckline.
Step 6:
Bring the lower edge (with the sleeves) up and tuck in under the collar to keep it in place.
Crease along the bottom edge of the shirt.
