Preparation Work Scenario

Hi
I have reached Bishops Lydeard in the Preparation Work Scenario scenario and I'm asked to Contact the Signal Box to request permission to proceed.
This message then disappears and then I'm told to Couple To Formation, stop close, climb down and manually couple the coaches.

Only there is still a RED LIGHT.
If I proceed I obviously fail the scenario.

So can anyone advise how I contact the Signal Box to request permission to proceed.

Thanks
Allan

 

With the "Tab" key

 

Thanks. I thought the 'TAB' was only for the opening and closing of the doors dugh!
Anyhow thank you for the info much appreciated.