This sets whether your variables are displayed as rows or as columns.
Rows / Columns
These let you define which dimensions (e.g. categories, scenarios, versions) to include as the rows and columns of the table. By default, Time is included as a column dimension.
If your model has its own custom dimensions, you can choose to include those. When including a custom dimension, you can automatically include dimension totals by hovering over the dimension and clicking the Total button.
Reordering variables
You can easily reorder variables in tables by dragging and dropping them.
Show table groups
If variables are grouped in the spreadsheet workspace, then the table will automatically display these variables under a group heading. If you wish you can toggle this off.