Sub-object mode lets you select and animate objects within a unit's hierarchy.
Select the unit you want to animate.
In the Story Editor, click .
This adds a new story and a new unit track in the tree view area.
In the tree view, right-click the unit track and select Add Sub Object > Object Name.
A new sub-object track is added.
Note: Picking a track auto-selects the appropriate node.
In the Toolbar, click to turn on sub-object mode.
In sub-object mode, you can select any of the unit's nodes.
Note: Sub-object mode persists when switching between instances of one unit.
Scrub to the frame or time you want in the Story Editor timeline, manipulate the sub-object in the Level Viewport, then press S or click to set a keyframe.