Q. How do I add multiple top roles to an org chart, so that they are side-by-side horizontally in-line?
A. Once you have one top role in place, you may wish to add another. Hover over the top role box to which you wish to add a parallel colleague in the same horizontal line. Click on the plus sign + to the right or left of the box. This is the feature "Add colleague right/left".
A new role box appears directly to the right or left of the original box (see below).
Here's a quick video: