It's fairly simple John. You put the pointers in the dimple on each end of the rod bolt and zero the indicator. Now you tighten the nuts until the stretch gauge reaches the recommended stretch. Check with the bolt manufacturer but if I can remember right the recommended stretch is in th.006-.0065 range. Like I said check with your bolt manufacturer, my brain is a little foggy this morning. Be careful not to let the gauge slip when tightening the nuts. This is actually the best way to tighten rod bolts. I spent some time one day checking the effects of different lubrication on rod bolt stretch and was amazed at the differencs from one lubrication to another. ARP lube was the only one that gave the correct stretch at the recommended torque. Something to think about.
