Just play with it a while, anchored between a fence & a tent stake, and you'll get it.

Like Malpaso said, form the thing as a largish loop, hook the loop on the stake. Grab the side of the loop that attaches to the fence (or top of tent pole, etc) near the stake and pull it taut. With the other hand, slide the slider UP the taut line until it can't go any farther.

Once you've got them all more or less steady, go around again and tighten all of them. Check them again if the wind comes up.

Sue