If you are talking about the plunger in the door jam area, the ring kinda pops off and you twist the plunger 1/4 turn (90°?) Then push it in
You have to take the upper and lower back seat out and the side panel off.
The cable system is connected to belt tensioner.
has a couple ear like things, take a pick and a small screwdriver and probe around under the outside edge, careful, they get brittle and I don't know if they make new ones.
They retract the belt when you open the door so the person in the back seat can trip over them and fall on their face when they try to get out.
You can't like somebody that sits back there anyway.