You can create hierarchy on your sheet by indenting and outdenting rows. Indented rows can be collapsed or expanded.
Indent Row
Indent a row to make it a sub-item of the row above:
To indent one or more rows, click on the cell(s) in the Primary Column you wish to indent and click Ctrl+K (keyboard shortcut for indent) or the indent button on the format toolbar. Ctrl+M is the shortcut to outdent.
You can right click on the primary column header to choose Expand All/Collapse All.
When you click and drag a row that has items indented below it, the sub-items move with the selected item.
Indenting will only be displayed in a sheet's primary column. Primary columns are noted by the column name being formatted in bold.
There is no fixed level of indenting. You can continue indenting rows on your sheet to create levels of hierarchy.
For more details on creating hierarchies, watch this video to step through the process: