Lay your poncho out on the ground and fold it in half lengthwise. Fold your poncho again lengthwise until it is about 12 inches wide. Fold the hood down for a uniform appearance across.
Roll the folded poncho into a tight cylinder. When you finish rolling the poncho, it should appear as a 12-inch-long cylinder with a circumference of about 6 inches.
Secure the consolidated poncho. About 2 inches from the edge of each side of the cylinder, tie a string or rope around the cylinder to prevent it from unraveling. Tie the ties as double-knot bows, as if you were tying shoes.
Tie the poncho to the frame of your rucksack. Thread a string through each tie you created on the cylinder. Then, thread the same string or rope through the frames on the rucksack and tie a bow knot. This will allow you to simply reach behind your back and pull the bow-ties apart if you see signs of a storm.