I have the material to install the headliner, however, when I purchased this vehicle the headliner was already disassembled. Supposedly the parts were there but unfortunately they are not. Can anyone tell me where I can get the restrainers etc. Not sure exactly what I am even missing.

Let's start with what you have. Sounds like you have the headliner itself and that's all you have. You'll need the bows to hang the headliner and some instructions.

Check out these threads...
http://www.chevelles.com/forums/showthread.php?t=107366
http://www.chevelles.com/forums/showthread.php?t=101101
http://www.chevelles.com/forums/showthread.php?t=107378

also search for "Headliner"