It has been several years since I am done this, but I am a bit confused by your note. If you have put in sound deadener, what "underlayment" needs to be glued in? In my (fading) memory, when the headliner comes off the only thing glued on the roof was the sound deadener. The headliner itself is not glued in. The ribs hold it in place, then it is stretched out through the brackets around the rim.

Here's what I did:

1) Pull the metal brackets with the teeth in them slightly away from the body.

2) Thread all the ribs through the headliner then put all the ribs in place, generally laying out the positioning.

3) Where there is the hard plastic rim go ahead and flip it into the slot.

4) Tuck the rest of the fabric up behind the teeth. When everything looks good tap the metal back toward the body. You have to hit through the headliner to do this. I used a deadblow hammer with a couple of rags over the end to protec the fabric.

Again, this was several years ago, but I did this 3 or 4 times in various cars and always by myself. Always came out tight and straight.