Different column widths for different pages

Hi,

First to say I am not great with php or css. I designed a template using the Artisteer software which is brilliant, and when I create a new page I can select the Default template or a one column template.

How do I create another template – but without much knowledge on css etc? I need a homepage with different column widths. Is it simply editing the css file typing in the widths or percentages I want?

Thanks