While the boat is at trolling speed, set your fishing reel to free-spool, apply slight perssure to the reel with your thumb and let your lure out to the desired distance.
Then set the drag clicker to stop your reel from free-spooling. Place your fishing rod in the rod holder.

Next, take hold of the fishing line (beyond the rod tip) in one hand. With the other hand, reach down and firmly take hold of the line release. Lift the cannonball out of the water and attach the line to the line release. Then ease the cannonball back into the water.

While firmly gripping the downrigger reel's handle, loosen the clutch knob (found on the left side of the downrigger) by turning it counter-clockwise. This will release the tension on the disc clutch plates that hold the cannonball at a given depth.

When you feel the weight of the cannonball pull on the downrigger reel, turn the reel counter-clockwise to lower the cannonball. Watch the line counter that is mounted on the top of the downrigger. The line counter is marked in one foot increments.

After your see the depth you desire marked on the line counter, retighten the disc clutch by turning the clutch knob clockwise until the clutch holds the weight of the cannonball.

Once you've set your clutch on your downrigger, set the drag and drag clicker on your fishing reel. Then take up the slack in your fishing line, until there is a bow in your fishing rod.

When a fish strikes or when you want to retrieve your lure, remove your fishing rod from the rod holder and abruptly lift it to release your fishing line from the line release. Then fight and land your fish or retrieve your lure.

 Finally, to retrieve your cannonball, loosen the clutch knob as you did in step 3 and retrieve the cannonball by turning the downrigger reel clockwise until the cannonball surfaces. Then tighten the clutch knob to hold the cannonball securely.