I put a head liner in my 72 chevelle and forgot to put the dome light screws in first. I cannot figure out where it goes, sounds lame but I've been trying so hard and I am stumped. Any pics or suggestions appreciated.

You do have the wire with the clips hanging though a slit in the headliner?
If so, look at you dome light base. Not sure on a 72 but a 67 has one screw towards the back and one forward of the clips. The screws are also offset. One towards the left and one towards the right. If your headliner is slit for this, look at the base and get an idea and then pull down on the headliner and look with a flashlight.
Hope this helps. I don't know....72 might be totally different.