To add your preferable elements to a template you must put them into a wrapper box called Section.
When adding a new section to a template, you can select how many columns it needs as well as choosing their structure.
You can also add a new column to a section after you created it and choose a structure for it.
To add a column to an existing section
1. Right click on the Edit button that appears on the upper-left corner of each column of the section.
2. Choose + Add New Column. A new column will add in right of the selected column.