To use the lists, you just have to click on the grey down arrow that is present in some fields. Almost all of the lists can be modified.
See the example of the Vehicle Typology.
Once open, open the elements management window by clicking the pencil icon.
Add or remove items to the list using the + button or the trash can in the menu. Edit the values by clicking on the field of a row. Save by clicking on the save button.
You can update the list by clicking on the refresh icon.