Place the nutsert into the frame rail hole. It should be really snug in there. If it is not you can jam some really thin metal in between the hole and nutsert to tighten things up.
Occasionally you will need to install a nutsert into your Jeep Wrangler. I had a stock nutsert break on me. Follow these simple instructions to install a nutsert into your Jeep Wrangler frame rail.