It is simple. You should be able to figure it out by looking at the picture.
Grab some rope or cord. Pictured below is approximately 1/4 inch 'clothesline'. Like a lot of my instructables, I used what I already had. Cut the rope into approximately 2 foot long pieces. Melt the ends if you so desire. Now tie each piece of rope into a loop. Use whatever knot you like. I think I used a simple overhand knot. Hold both cut ends in one hand, make a loop, pull the ends through the loop and pull it tight.