Installing headliner '71 dart swinger

The umbrella type headliner will be the most difficult R&R you'll ever do. Even with the front and rear glasses removed it's a chore. There are some tutorials on line that will help.
One thing I can add , cover the cars floor with old blankets or similar. The rear seat anchors can draw blood from your knees. I cover those with hub cabs and cover the hub caps with blankets.

^^^^

What RedFish said.

I would take it a step further.....have it done by a pro

I tried putting my own it. Hardest thing I ever tried to do
on the 'Cuda. Ended up taking it to a pro to have it pulled
tight and glued.