1. Start Eclipse.
2. Go to Help –> Software Updates..
3. Click Add Sites.
4. Set the Location to “http://www.adnsandbox.com/tools/ide/install/“, then click “OK.”
5. Check Force.com IDE Update Site and click Install…
6. Check Force.com IDE and click Next.
7. Check I accept the terms of the license agreement and click Finish.
8. Restart the Eclipse.
9. Once Eclipse restarts, select Window > Open Perspective > Other and select “Force.com”, then click “OK.”
Or visit the below link
