Newbie today, I wonder if anyone can help? how the heck do you green up, example today my bank allows a stake of £200 so layed at 4.1 waited for the increase backed @ 4.4 tried to green up by hitting the green column but all it did was lay another bet which I didn't realise that is was doing that so tried again then noticed I had 4 lay bets and 2 back bets so to sum up the horse won and I lost £680 I now know the green column is not for greening up not sure what's it's purpose is really apart from putting laying more bets, so I would be most grateful if someone could advise me how to green up

Thank you inb advance
Regards
Chris