Below is how I achieved that look. Of note, you must purchase the ribbon that is wired on the sides. The width really doesn't matter. I used two sizes on this tree.
#1.Cut ribbon anywhere from 18" to 20". You really don't want the lengths to be exactly all the same.
#2. Fold the cut piece of ribbon in half.
#3. Twist the ribbon at the fold, two or three times tightly.
#4. Bow the ribbon as shown.
#5. Tuck the twisted part of the ribbon into the tree, and make the bowed part look like a loop on the tree.