I've used one to put fences up around the farm. The barbed wire goes into the slot of the curved arm, the straight arm goes into the wooden post on the far side, you pivot on the straight arm pulling the barbed wire tight. Then your helper puts in a U nail wooden post to keep it taught. One can do it by themselves, a magnetic tipped hammer to start the U nail, finish with a second hammer works, wearing gloves and tough jeans a must cause it is gonna get you! In between the wooden posts are the metal ones, they get the barbed wire wired to them, so you are putting tension on 40-60' of wire it's hard work. I haven't used mine in 25-30 years and happy I haven't had to! It's hanging on the wall of the barn somewhere?