Its a snap. Liner should come with instructions.
Hope u have old liner. Makes it easier if seats are not in car.
I have replaced my AAR headliner twice. 1985,2006.
Lay out the new liner in a warm room , over cloth line if u have basement couple days or lay out in the sun half hour.
I wouldn't install in cold. Liner should be warm and flexible when installing.
If u have the original headliner even if ragged.
Lay old liner on new liner, line up bow inserts.
Cut the new liner at least 4 inches larger than old, all the way around.
Have the top front and top rear trim ready (painted) when installing liner, screws, bow clips.
If u don't know where bows go put them back into slots in the car for lengths.
Place bows in liner.
start installation in middle of roof (dome light between bows)work to front and then to back.
Do not cut out the dome light until it is installed. make sure the wires and bracket are for dome light are in correct spot.
Don't cut until u are sure of fit, snug it up Front and rear. then start on sides.
Install side trim don't cut until everything is smooth and fits.
U will need another hand (s) to help if u don't have the old liner.