Door locks on '88 Volvo 240

I recently had the door lock system replaced on my 240, and I don’t think they work like they used to. Can someone describe how this model’s door lock system should work? For example, when I walk up to the car and unlock the driver’s side door, the locks all unlock (good). When I get in and start the car, should (a) all door locks automatically go into the lock position, (b) all doors go into lock position if I manually lock the driver side door, or © all stay in the unlocked position? And, what happens to the door locks when I turn the car off? Many thanks.

If you have the owner’s manual for this car it should contain a description of how the locks work.