O2 sensor z71 2001 bank 1 sensor 2

Need help on which sensor it is? The autozone guy told me it is just after cat and on drivers side. But exhaust doesnt go on drivers side. And his computer and other places on web say it takes two of these and they should be done at same time. Looking underneath truck I only see one just before cat and one just after cat and they both have different connectors. Do i need to do two and which one(s).

Look at the exhaust from under the truck as it leaves the driver side. There is 1 cat on each side before the collector that puts it all into a single. Unless you have a unique truck the exhaust is pretty much standard.

I see the one before and one after drivers side now. So bank 1 sensor 2 is drivers side after cat? and do I need to replace both after cat like some recommend or just the one failing?

also can i reset computer by disconnecting battery for a few minutes after I do the repair or do i have to pay someone to reset it?

When you say reset you will be loosing the learned information that the truck has learned over time. The main program is still there and yes you can unlpug from the battery. Some say 10 minutes others say over an hour. If you are working on the truck go for a while to ensure it gets done.