The Link Occurrence Units and Classes wizard allows you to choose which units should be associated with particular classes, by displaying them in a simple grid layout.
You can access the Link Occurrence Units and Classes wizard by right-clicking on either the Units/Modules heading or the Classes heading after selecting an Occurrence, and selecting Link Units and Classes.
The wizard will display like so:
To associate a Unit with a particular Class, tick the corresponding box within the generated grid. Multiple Units/Classes can be linked in this way. The Use column can associate all units with a particular class.
Press Next and Finish to complete the wizard.