Creating a budget line for more than one set of data

[MHunter]

Hi,
I am creating a budget line for a city's spending on bread and vegetables. I have managed to do this with no problems but now I need to add another city's spending on these items onto the same graph. And then a further 3 cities, each with a different coloured line. Is someone able to give me some really simple step-by-step instructions on how to do this?
Thanks for any help!