Cut headliner from the center toward the edge of the hole stopping just short of the wood (1/8" to 1/4") as shown in the attached diagram. The flap created at the light socket just folds loosely inside. The remaining flaps require one small tack each inside the lamp pocket. If after cutting the slits, the headliner seams pull slightly away from the lamp area, draw the fabric slightly and PIN TACK flaps in place. Be sure to draw fabric just enough to return liner to it's natural position, or the result will be puckers around the lamp.
After you are comfortable with the appearance, set the tacks the rest of the way in and install the domelamp. The lamp helps secure the fabric. Adhesive is unnecessary (and if it drips anywhere you will have to live with it!).