Position of Heat setting switch please?

My Creda Reversair Model is number 37642 series 23102959. My wife has died since buying. It is at least ten years old, I think and it does well But I don't understand the heat setting switch. Should I press it towards High if that is required and conversely towards Low for acrylics? It is only when it is pressed downwards towards High that the switch exposes a green bar....and that green bar is at the top near Low. Please help.