Select the Subgroups tab, and then select Create Subgroup.
Create Subgroup options on the Subgroups tab
When you create a subgroup, you must enter the information identified as editable in Details and Settings. The parent group field is automatically selected.
Create a subgroup
After you enter all the required information, select Create Group.
Any user quota that you assign to a subgroup is instantly deducted from the quota of the parent group.