Citroen c3 Diesel 1.4hdi Cold start/glow plugs?

Hi don't own a Citroen myself. When you switch on with all the lights on dash board showing but you've not yet started the engine . Look for a yellow light that has a symbol that looks like a spring in it.Wait till this goes out and then start the engine. You only really need to do this when starting from cold. If the engines warm the the light may not even come on.