Assembly Design > Using Assembly > Placing Components > Unplaced Components > To Include an Unplaced Component
  
To Include an Unplaced Component
1. In an open assembly, click Assemble > Include. The Open dialog box opens.
 
* You can also drag a component into the Model Tree from the file browser.
2. Select the component to be included in the assembly.
3. Click Open. The component is added to the Model Tree but does not appear in the graphics window.