Once you selected "div" in the menu tabs, you can enter the number of columns and rows in the interface below:
monosnap.com/file/h8c5UQZegOwoBpQp9qZSCpXiumUzGS
If you have several columns configured there but you don't see that on your frontend it's either that you're not looking at the correct menu item, or that your template CSS or view overrides mess with the display of the listing. So check with the default template of Joomla and see if that helps to see if that comes from the template or not.
