Isn't this an Automat series camera?

Automats don't have a start mark. There's a small silver roller near to the bottom film compartment. The film leader goes UNDER that bar then over the film gate and on to the takeup spool.

Turn the film advance lever about a half a turn to be sure that the film is taking up smoothly as it should then close the back and lock it.

That little roller you put the film under will detect the presence of the film as you roll the advance lever. Film counting will start automatically.

The whole mechanism resets itself when you open the camera back again to replace the film.