Location of oxygen sensors on a V6?

I am trying to locate all the oxygen sensors on my camry. There is a picture floating around online but I don't think it's the correct one for my car.( I have attached this picture)

I know that my car has 4 Sensors Two of which are A/f sensors.

Upstream front
Upstream Back
Downstream Front
Downstream Back

I think the Upstream front is the one that comes directly out of the front of the manifold but that I pretty much the only one that I know.

A garage told me that I needed to change Bank 1 Sensor 2 and Bank 2 Sensor 1. Now I just have to locate them on the car. I have my Haynes Repair Manual but it doesn't give any information.

Thanks in advance for your time and anticipated feedback!