Has anyone got a step by step guide on how to connect ,got a different truck last night ,had these on ,not a clue how to connect to the trailer
That truck must be old couplings were not used much in the uk,with some working out and common sense .you had a night off .no air
This could open a can of worms.
Marmite Couplings 
I have used them for many years and never had any issue with them, in fact every country in Europe and most of the world use them, yet people seem to be scared of them. Glad Hands in the US, Palm to us limey folks