Create Packaging
Go to the Packaging tab (at the top of the menu bar) and select Create Packaging.

Class: Select packaging type
Type: Select the correct unit
Consists of unit: For F-pack, the price unit is inherited
Consists of count: Quantity in relation to the price unit (applies to F-pack)
GTIN: Enter the Global Trade Item Number
Height: Enter gross height in millimeters
Length: Enter gross length in millimeters
Width: Enter gross width in millimeters
Weight: Enter gross weight in kilograms
Custom volume (m³): Can be entered as a custom value if the calculated volume doesn’t match the shape of the packaging
Deliverable: Indicate if this unit can be delivered
Stocked: Indicate if this unit is kept in stock
Once the information is entered, click Save.
If you want to register additional packaging units, follow the same procedure. See here.
An overview of valid units for price unit and packaging can be found here.