From what I recall, it's a straight forward installation. The strap side is mounted to the post with a press pin, just remove the lower retaining clip, like a c-clip with a little 90 deg lip on it, drift the pin upwards and the strap will release from the pillar. Make sure to secure the door so that it does not open too much more than where the check strap held it at wide open. From there unbolt the strap assembly from the door , should be three bolts and I believe that the bolts go in from the outside of the door and screw into the mounting tabs of the check strap assembly. Either way the assembly mounts from inside the door frame and the screws/bolts go in from the outside.

Another thing to note is the position of the loop end of the strap. the side that mounts to the pillar. The sheet metal is rolled to form a loop, and the loop favors one side of the strap. Just note how the originals are mounted and duplicate that position with the new strap. I believe the bulge portion goes towards the centerline of the car, but just match up to the ones you are about to change. I believe the checkstrap is the same part number regardless of left or right side, front or rear.

If your straps are painted the same color as the car they are original. The new straps have a gold-tone cadium coating and a plastic sleeve to act as a vapor/water barrier which many originals do not have leading to the early rust-prone failure of the originals.

The hardest part of the job is getting the panels off, the rest is a walk in the park.
Best of luck,

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)