Above the Data Map, there is a title referring to Manual Metadata which indicates to "Create".
Once selected, already a coloured cube is observed next to Manual metadata.
Like in Metadata creation, a pop up appears, in which known information can be filled in or selected.
When complete, the tick can be clicked to create Manual metadata.
This can be viewed by hovering your mouse over the coloured cube and selecting it.
If Metadata is created the standard way by selecting the cube function, there is also the function to make this metadata manual by selecting "Click here to make the edited metadata manual".