I did it not too long ago on my daughter's car. It's quite simple.
With a 27MM socket, the injector socket works great, turn the crankshaft clockwise to TDC slowly. With the valve cover removed, the marks on the camshaft and front bearing pedestal should line up. If the mark is not in sight, turn the crankshaft one more full turn clockwise slowly to TDC. If the mark is off much more than a degree or so, you can worry about it. If the oil has been changed frequently, which keeps the particulate matter out of the chain, you should not see any stretch.
It is not wise to turn the crankshaft at all counterclockwise, this will be turning against the rails. When I say clockwise or counterclockwise, I mean as you are standing in front of the car looking at the engine.
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in