G12 - manually turn engine

[Froodme]

Hi. I'm planning to clean my intake manifold (carbon). I'm fine doing the removal and cleaning the valves for the closed pistons, but anyone know how to manually turn the engine and close the intake valves on the others (so I can clean them too)?
My vehicle is a 2016 740LD G12 with the twin turbo B57 engine.
There doesn't appear to be a nut/bolt on The end of the crankshaft, so I'm a bit stumped. I'm intending to have the battery disconnected during the clean, so I have to turn it manually by hand.