placement

kk I have a 2000 ford ranger 4.0 v6 I am replaceing an o2 sensor. Well I have 3 one on drivers side as pipe attaches to manifold, one on passengers side same place, and one behind the catilac converter. Can anyone tell me which one is would be spot 1?, the diagnostic I got said "oxygen sensor in spot one faulty" out of the three which one is spot 1. I believe it to be the front one on passenger side... please help