This is similar to a Thangle.
http://www.blockcentral.com/hst/hst-1inch.pdf
The directions for it's use are very well worded. Sew on the dotted lines, then cut on the solid. A thangle is one long strip that comes on a roll like toilet paper. Use what you need, but don't waste. (sorry about the comparison.) These come in different sizes, and you can find them at www.blockcentral.com
I will never, ever try to make HST or QST without them again. :D