There is a 10 page detailed description in the factory manuals.

It consists of connecting pressure guages into the fuel distributor system to measure fuel pressure and lower chamber pressure alternatively. The differential needing to be .4bar.

It obviously requires some setting up and the proper equipment.

Whilst my warm start problem is not completely resolved the car is otherwise transformed now I have this setting right.

If I want to go to the next step I believe I need to change the fuel injectors.