If you poke your head under the car you can see the O2 sensors, all four of 'em. You can even see where they're plugged in! Honestly, if a person isn't mechanically inclined enough to be able to get under the car and identify the O2 sensors and formulate what tools they would need to replace them - I don't want them attempting it.
There are some procedures on this car which really do require specific pictures and instructions before they make sense - but this isn't one of them.
