Cut three strands of ribbon in your school's colors to about 3 feet long. Cut a single strand of one color and two strands of another color.
Line up the strand ends on your cardboard. Place the ends on top of each other and flatten them out with your hand. Push a tack into the cardboard to hold them in place.
Thread the middle left strand underneath your far left strand. Do the same with the two right most strands as well.
Pull the two far end strands toward the center and over each other. Straighten the two middle strands, pulling them gently downwards, with the far right strand going underneath the right middle strand and the fair left strand going over the middle left.
Continue threading the four strands together in this method until your braid is as long as you desire. Cut any extra ribbon off with scissors and tie the ends together with string.
Push a safety pin through one end and use the pin to attach it to objects.