Connect one side of the fencing to a post by bolting the tension bar to the three center tension-rod brackets on that post. To attach the other side of the fencing to the opposite post, pull the fencing tight, slip the tension rod into the bracket, and bolt in place (Image 1). This is a two-person job: one person pulls the fencing tight while the other bolts it in place.
Bolt the headboard to the wall with the remaining two brackets.
Add an end cap to the top of each post to finish the headboard (Image 2).