Basically there's a CUWP Slot (Create Unit With Properties Slot). It's a template of unit properties (template like a layout for the properties a unit may have). You edit the slots (templates) and apply them to the units that you create (with the Create Unit With Properties trigger).
Read SCMDraft2
TrigEdit FAQ for info on how to do it with SCMDraft2. SF does not currently support the CUWP Slots so you will need to create them with a different program (SCMDraft2, PROEdit, uBeR@TiOn, etc.)