' 65 barracuda headliner instalation questions????

Upholstery guys have hand tools to use when attaching the headlinner to those cleats hidden under the window gaskets. You could make your self some hook like tool. If you're like most do it yourselfers you'll never want to do another umbrella type headlinner install in this life.
The best advise I can offer is be sure to cover the rear seat anchors and such . Protect those knees :)