I use 2-3 oz. of slivered chunks, at 140 for 2 hours. Then, put the fan in place, and keep the box temp at 140 until the jerky is dry. The idea is to not cook the cured jerky, but to smoke it & dry it. If it's done right, it will almost have a translucent look to it that you can see light through. No light = cooked.
Check out some of the posts, here, in the Jerky section and I know you'll find lots of answers.