first thing I did was to remove the headliner board then tear out all the factory tar paper on the roof and put in a layer of "Quickroof" it is like dynamat just way cheaper 15.00 for a 6" x 16' roll
and here it is in my wagon I used 2 rolls of the stuff for complete coverage
the put a complete layer of thermal barrier
then stripped the headliner board down with a hand wire brush to remove all the old foam then used 3m hi strength adhesive and alot of it to put up the new headliner material
Now I am waiting on the clips that I ordered to come in to put up the second section of headliner and the garnish moulding