I use an SCA 346/2 M1 AF adapter on my N8008S. The adapter attaches to the camera's hot shoe. One end of the SCA 300A cord attaches to the top of the 346/2, the other plugs into the flash. Set flash and 346/2 to M for manual flash, both to A to use the flash's own little thyrister controller, both to TTL to have the camera control the flash TTL.
The 346/2 requires 4 AAA batteries, IMO eats them. Always have a set of spares.
I don't often use mine with the SCA 300A cord, instead put a 305A multi-connector adapter on top of the 346/2. This lets me use the long 305 V5 cable for TTL control of a remote flash, would let me run 2 SCA 300 flashes with TTL control if I had two.
FWIW, my SCA 300 flash isn't a Metz, it is an Agfatronic 643CS.
I know that your 346/2 is an M4, not an M1 like mine. I suspect that they work the same.