I have a toyota trueno 1992 and i want to put a new stereo in it
Go to the auto parts store and get a wire adaptor made for a 1992 trueno. It will plug into your factory harness. The wire colors are prematched to your sony and other aftermarket stereos. Just match the wire colors, splice with connectors making sure no wires are exposed. (A little electrical tape for good measure around splices helps). Then it just plugs in. If your factory stereo has mounts that screw onto the radio, unscrew them and attach them to the sony. Remove sleeve from radio and discard. The screw holes are already on the sony.