There is a video about operation of both gas and diesel heaters in our Campervan 'how to' section.
Our In Vehicle Tablet also includes information about operating your diesel heater.
A minimum of 11.5 volts is required on your auxiliary [house] battery for ignition, there needs to be more than a quarter tank of diesel in your fuel tank. Turn dial to full for 5 minutes before resetting to a moderate temperature. Generally it will take 1 litre of diesel to heat your motorhome for 4 hours, to a moderate temperature.
If you have problems please contact our On Road Assist team, phone 0800 788 558. (We recommend a local sim to be able to contact us free of charge.)