The Unit manager window shows the list of defined units and also allows you to edit them. The window consists of three parts:
On the top, there is a edit box with list of unit quantities like length, angle or reference. Choose the one you want to work with (view, create, delete, or edit). The list below will be refreshed – only units of chosen quantity will be displayed.
The biggest part of the window is the list of displayed units. The unit's name is the name displayed in unit lists in property editors. The multiplier (against a certain unit) defines the unit's value. For example, if you want to create a unit for kilometers, set the multiplier to 1000 (against meters). The multiplier is then recomputed against an internal unit value.
The bottom part contains 4 buttons: