To adjust it you will need to have your ignition on but not with the car running, this will energize the EEC & the sensors.
To check the setting as it is you will need to use a digital multi-meter, & some basic wiring knowledge.
The Black wire is your ground the orange is your 5 volt reference wire & the green is the EEC feed wire.
Probe the green wire with the positive lead & the black lead to the black wire.
You may see readings from the mid .70v up to 1.0+v, the range that it is typically set at is .95-1.00v.
Loosen the top two screws & turn it clockwise or counter clockwise until you get it in the specified voltage range.
If you cannot get it into adjustment as it is you will need to remove the sensor from the car.
Once removed from the car use the small drill bit to elongate the holes in a crescent shape.
Reattach it to the vehicle, & adjust it until it reads Between .95-.97v . Tighten down the two screws & turn off the key. You do not need to reset the EEC, as it is really not necessary.