|Manage → Levels|
|This command is part of the BIM AddOn, that you can install via menu Tools → Addons Manager|
The BIM levels manager allows you to manage the different levels (also known in other BIM applications as floors or storeys) of your model. It lists all the Arch BuildingPart objects found in the active document, which are used to represent levels in FreeCAD. From there, you can change their settings individually or all at once.