What you need:
Ribbon in colors of your choice (I used four colors)
Twine to hang your garland
There really are no measurements that are standard to make this. You just need to figure out how long you want your garland to be. I cut my ribbons into long strips, doubled it and tied it to the twine using a slip knot. (The same knot used to make a tutu).
I tend to buy my ribbon at Michael's when I see that they have a great sale going on or I have a good coupon. I think it would also look great with different ribbon textures and patterns mixed in.
This is something that you really can't mess up! Get creative with it!