I bought mine and am saving it for last. I found this method on RestoRicks site from Moparts here:
http://www.restorick.com/tech/topic.asp?TOPIC_ID=5It is similar to Johnrez's method.
1. First step is to make a sketch of the positioning of everything fastened to the headliner. This includes items such as the rearview mirror, visors, seat belt clips, coat hooks, shoulder belts, dome lamp, etc. If possible, a couple pictures can be very helpful, too.
2. After removing the original headliner, be sure to note the correct order of the bows. They are different and must be reinstalled in their original place. If they were previously removed and mixed up, they can be laid out side-by-side and sorted for position.
3. If the car already had the headliner removed, be sure that the dome lamp wiring is in place correctly and if your model has brackets for the shoulder belt clips they should be there as well.
4. The new headliner comes folded in a small box. The headliner may be laid out and warmed in the sun to relax out wrinkles, but it is not absolutely necessary.
5. Start by sliding the bows into the listing pockets and centering them. At this point carefully trim the listings so that about 1" of the bow is exposed. (This step is done outside of the car.)
6. Now move the headliner with bows into the car. Place the rear-most bow into the hanger clips. On the rear bow there are 2 small wires with hooks on the ends. One end hooks on the bow and the other presses into a small hole in the rear-most roof crossmember. There's one wire retainer used per side. I like to hook them slightly inboard so that as the headliner is stretched to the sides it will pull them straight.
7. Continue placing the rest of the bows working forward.
8. Now for the most important trick!!!... you need about a dozen or so small spring clamps. Some refer to these as Pony clamps; the ones with the orange dip coating on the tips and handles. These are used to clamp the headliner edges WITHOUT stabbing it onto the gripper teeth. These will allow you to work your way around the headliner gradually pulling it tight and drawing all the wrinkles out.
9. Start in the rear by verifying that the centerline marked on the headliner is lined up with center of the rear window opening. Pull the headliner rearward and clamp it in place. DO NOT PRESS IT INTO THE GRIPPER TEETH AT THIS TIME!!!
10. Again, in the front verify the centering and pull the headliner forward and clamp it in place. Once again don't press it into the gripper teeth.
11. Now work down the sides, pulling it gradually from each side, clamping it along the way. As the headliner is pulled outboard, the listing pockets will need to be re-trimmed; trim so that approx. 3/4" of bow is exposed up to the roof side crossmember. Be consistent with this dimension so that the point where the side-to-side stitch seams curves is the same down the whole side. Continue pulling & clamping around the perimeter until the headliner is taught.
12. When the entire headliner is tight and looking good, you can go to the next step. First check that the front and rear side-to-side seams are straight. Uneven pulling can make them uneven, this is easily corrected by readjusting. It should look nearly perfect at this point and be taught. Small tight creases from packing folds will come out easily with careful heating. Overheating will melt the material! Practice on a scrap piece if you're unsure of how hot you can make it. It's also important to keep moving around with the heat to prevent overheating a spot. Time in the sun will also relax out these packing folds. Soft wrinkles by the visor corners will be pulled out as these edges are glued.
13. Starting in the rear, pull slightly and press the headliner material onto the gripper teeth. Start in the center and work toward the outsides.
14. Repeat step 13 on the front edge.
15. The sides are done next. This area has to be glued with trim adhesive. I use a special glue gun with a pinpoint spray pattern, but it can also be brushed on. Glue between the clamps and install headliner clips at each seam. Trim edges to approx. 5/8". Remove the clamps as each section is dry enough to hold.
16. Trim and glue down areas in front next to the visors.
17. Pull headliner to eliminate wrinkles and push down onto gripper teeth in the sail panel areas. Supplemental glue is recommended along the bottom. Trim as needed.
18. Finish trimming around the front and rear edges being careful not to cut too close to the teeth.
19. Carefully locate the dome lamp position. Refer to your drawings or pictures to be sure. One wrong cut here and its back to square one! On many cars, the dome lamp can be attached in front or rear of the center roof crossmember. Be sure you have it in the right place... make a small slice and locate the wiring & socket. Only trim the slice large enough allow the lamp to be screwed on without distorting the headliner. Cutting an opening is not necessary or recommended.
20. Visors, mirror, etc. can be located by feeling through the material to find the indents for the screws. A small needle can also be used to check if you're unsure. Take your time! I haven't scrapped one yet, but I've come close!