Click the PathFinder tab.
In the top pane of PathFinder, click the assembly you want to expand.
On the shortcut menu, do one of the following:
Click Expand to expand only the active assembly.
Click Expand All to expand the active assembly and all the subassemblies within the assembly.
Tip:
You can also expand and collapse an assembly by clicking the plus (+) and minus (-) symbols adjacent to the assembly name in PathFinder.