The LeadGantt interface is divided into different sections so that you do not need to do any formatting. However, you cannot insert rows or columns in any of the sheets. If you do so, it will break the code and LeadGantt will not work as expected.

If you accidentally happen to insert rows or columns, then you can undo it using the Undo function (Ctrl+z), but there is no guarantee that LeadGantt will function correctly. So the best way is to create a new sheet and start over again. 

The below screenshot shows the LeadGantt interface:

LeadGantt interface has the following components:

1 - Three master sheets, a Help Sheet, and a Baseline sheet of your project.

2 - The sidebar.