To select an effector: 
- Select it in the Viewer window or click its corresponding cell in the Character Controls window > Character representation 
 
To select multiple effectors:
- Ctrl-click to select them in the Viewer window, or Ctrl-click multiple cells in the Character representation 
 
To select all effectors in a body part: 
- Shift-click an effector within the body part hierarchy that you want to select. For example, Shift-click the left wrist to select all effectors for the left arm.