When the page is generated with keys, the keys are inserted into the code and then they might change the look of the page. The layout numbers are there to help you locate the keys. For example Layout 8, h5up01_cont4u has 3 items connected. One image and two local text.
When the code is generated without keys, the page is correct displayed. This template by HTML5UP n33 is a responsive page. When displayed in a pc the page are divided into 2 columns. The page has always a size of 12 units. You can combine any combination by using 2u, 4u, 6u, 8u, and 12u. You can read more about it at skeljs.org if you want. But to make it simple, 6u + 6u = 12, 4u + 8u = 12, 4u + 2u + 2u + 4u = 12 etc
When the page is displayed in a mobile device there is just one column.