How do i light the pilot light on a Vaillant combi VCW Sine 18T3WFH?

Hi

Have moved into a property with an old vaillant boiler which has a green button a red button and a grey knob.

Boiler has gone out and now i need to relight it, reason for boiler going out was the gas was switched off so it hasnt gone faulty. We were warned these boilers are hard to light which is no help now as it is late at night and cold.

Can someone please give me a basic answer on what to do, i have already been to the Vaillant site and requested a manual but until then i'm stuck.

Cheers