Via the tab called "Supplement objects" you can manage supplement objects. However, supplement objects are best managed via Buildings. Via Buildings you can manage supplement objects for both buildings and land objects.
For more information on how to
manage supplement objects for a building, see section 8.3. in the manual for Buildings
manage supplement objects for a land object, see section 10.6. in the manual for Buildings.
You will find the manual here but you can also open it via the Manual icon in Buildings.
