Unfortunately, the link you’ve provided doesn’t seem to work.
The menu card works on the basis that each column is populated by a category, if that category has sub categories, they also display in the same column. So if your posts structure, is placed all the content as sub categories, under one main category, then it will appear as one long list.
To ensure both columns are filled, make sure each that each category you add is independent and doesn’t have any sub categories unless you specific want a sub category to appear on that page.
Also make sure in the settings you have not checked the ‘one column’ menu card setting – http://screencast.com/t/VpRxmWT19