Add columns to your site with the Columns element. With this element you can add a maximum of 3 columns.
To add more columns:
Drag and drop the Columns element from the Elements tab to your page. You will have two columns on your page.
Again, drag the Columns element and drop it in the column on the right and repeat for the column on the left.
You will have four columns on your page. Continue adding columns to the right and left to add more columns.