P0140 troubling code

? I retrieved the Code P0140 out of my '02 Silverado VIN Code "W", and so I have decided to replace the O2 sensor identified as Bank 1 Sensor 2, the only problem is, I don't have a service manual yet, (I'm tryin to get it online) and I need to know which is bank 1, the driver side or the passenger side? I know that is the same as where cylinder number 1 is, but without anything to use as a reference my brain is useless, ( a little more than usual).
Any help would be greatly appreciated.


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