You must take great care when assigning polygons to each bone in order for your figure to be able to bend and bend correctly.  Do this by creating named polygon groups and assigning the appropriate polygons to each group.

Each existing bone or body part needs an identically named polygon group on the figure.  Each of the figure's joints causes polygons to bend where parent and child groups meet.  Poser uses the bone's internal names, allowing the visible names to be localized to different languages.

If a pre-existing figure was selected when you entered the Setup Room, the necessary body groups will already be available to you and may already be properly set up.

The Auto Group button in the Group Edit palette is the easiest way to assign group names to the polygons of an imported prop for the first time.  The Group Edit palette displays when the Group tool is selected.

NOTE: Only use the Auto Group button after you have created and positioned a bone system.

NOTE: Auto Group will completely regroup every polygon in your model.  You will lose all pre-existing group assignments which match bone names.
 

NOTE: The Group tool automatically removes  polygons from  other named body parts as you assign them to new groups. This is not true for Group Edit palette commands.

NOTE: Removing  polygons from a body part group adds the selected polygons to a group called NO_BONE, which will allow you to easily rectify this situation before leaving the Setup Room.

Keep in mind that joint bending only occurs between an object and its parent. Bends do not progress to other children or above the parent in the hierarchy. Create your groups and tweak your joint zones with care to ensure proper articulation.