This is how to control the Blog Layout (specifically Columns)

To control how articles are displayed you need to:

• Go to Menus
• Select either MainMenu (along the top) or Left Menu (down the left)

So for example go to Menu / Left Menu and click on one of the menu items (e.g. News)

On the Right side click on Parameters Basic

#Leading - Number of Articles to display full width along the top
#Intro - Number of Articles in Intro Text (underneath Leading)
Columns - Number of Columns to display Intro (2 means side by side in 2 columns) - (1 means underneath each other)
#Links - Number of Articles to display as links when the Number of Leading and Intro have been used up