I have an existing account but would like to have more than one farm to help each other. How do I create..

You can create as many game / bases as you want. But each one needs to be bound (linked) to a separate external account to save it. Once your current game is successfully bound you can go to the Settings -> Account screen ans choose 'Start a new game'. This will let you create a new game which you can move to your current state (before level 6) but you must bind it to a different IM30 account (different email) so that you can log back into the old game with the previous details.