We used 5 lb, bell-shaped anchors at each turn ball. First, we installed the course, then we attached one end of a rope to the anchor and the other to the end of each pole where the turn ball attaches, pointed the boat upstream, pulled until the arm was straight, and dropped the anchor. It worked when we put the anchor in the right place, but we hardly ever got the anchor in the right place. To get it right, you need a second, non-floating rope off each anchor, and you need to use this rope to drag the anchor into the right spot and set the anchor down gently. To eliminate guesswork, you need a second boat or a person on shore, so an observer can tell you when the arm is straight. When you're pulling upstream and guessing where to drop the anchor, you rarely get the anchor in the right place, and it will ruin your day.
We did OK with this method, but it took so much time to set up and take down that we eventually gave up and moved out of the river and back onto the lake. We loved the isolation of the river, but set-up time, plus the occasional log floating through the course, made it more trouble than it was worth.