There are headliner retainer bars that keep the PV444/544 headliner in place. It is a bit of a puzzle figuring out where they go, so if you take them out note where they went (when I bought my car they were lying in the back seat). Once you figure that out, the rest isn't too difficult. There are teeth (probably rusty) that grab it and hold it in place so you really only want to install it once so make sure you line it up right. I started at the front and worked my way to the back. There is a spring under the back window that holds it in place back there and it is in a fabric sleeve that will probably be rotted and need to be replaced (I just sewed a new one out of nylon). The tension in the back there is still not quite right in my car, but I was pretty happy with it. After install you have to cut a couple holes in it for visors & dome light, so make sure you line everything up before doing so (grrrr, I didn't).