Multicolumn layout?

I’m just new to www.ads-software.com – I’ve run a blog on wordpress.com for a while now. And I’m looking at mainly text-oriented themes, of which Carton seems excellent. But how do I obtain the multicolumn look of the sample page? In the Layout block of the Customization menu there are options for the width of the column and sidebar (both in pixels). But I can’t find an option for making several columns, or as in the sample page including several columns below a single larger block. Or is this all done with html tables? (In which case I’ll have to go back to html school, as I’ve totally forgotten what little I ever knew).

Thanks!