Optimus 120-1998 - Manual (Page 6)

Connecting the Antenna and the Battery
Connect the vehicle's antenna cable to the stereo's large black antenna
connector, then reconnect the cable to the vehicle battery's negative
terminal.
TESTING THE CONNECTIONS
Turn on your vehicle's ignition and test the stereo.
If the stereo does not work, immediately disconnect your vehicle battery's
negative (-) terminal. Then, recheck your connections, or have a
professional auto sound system installer install the stereo.
After you test the stereo and verify that everything works, make sure the
connections are correctly marked or identified.
MOUNTING THE STEREO
Be sure you test the stereo first and verify that it works properly.
Follow these steps to mount the stereo.
1. Disconnect the cable from the vehicle battery's negative (-) terminal.
2. Temporarily disconnect the wiring harness and the antenna.
3. Insert the supplied sleeve into the dash. Then secure the sleeve to
the dash by bending out the appropriate tabs with a screwdriver.
Bend out all the side tabs.
4. Reconnect the wiring harness and the antenna.
5. Slide the stereo into the sleeve until it locks into place.
6. To further secure the stereo, use the supplied hardware to attach one
end of the supplied metal strap to the back of the stereo. If
necessary, bend the metal strap to fit your vehicle's mounting area.
Then attach the other end of the strap to an existing bolt on a solid
metal part of the vehicle.
This strap also helps ensure proper electrical grounding of the
stereo.