How do I lock the doors on my used Mercedes?

[CommanderCrusty]

I just bought a used 1992 C-230. Nice car, but how do I lock the stupid doors? You can't just lock them by hand--they won't go down. The key fob has what seems to be a lock button, but pushing it, even right in front of the lock, won't lock the doors. There isn't even a place on the drivers side door to put a KEY into the darned lock. Please help me understand the German thinking on this vehicle. Thanks.