How to create 2 or 3 column layout??
Very simple, login to your admin panel, now go to Extensions » Modules now click Edit link beside Category.
Now click on Add Module button, you will find new filed generated, now select
1.Layout = Home (For Home page )
2. Position = Column Left or Column Right
3. Status = Enable
4. Sort Order = 1 ( 1 display top, 2 display below 1)
Now click on save button, thats it! This is the same way to add other modules, and assign to columns you prefer.
Once you assign modules to Left and Right columns then theme automatically becames 3 columns. If you assign only one column Left/Right then theme becames 2 columns.