Auror Requirements

I have read the Adult Character guide thouroughly, but Auror requirements were only mentioned briefly.  The entry is this:
Auror - Minimum of 5 N.E.W.T.s (recommended: DADA, Charms, Transfiguration, Potions and one additional) and completion of Auror Training

What exactly does Auror Training entail, and how long does it take?

From my understanding it takes 2 years and it's shadowing a trained Auror.

2 years?  OK, thank you   Also, do you think that trainees practice skills and duels with other trainees when not with their respective Aurors?

That says 3 years, so I will go with that.  Thank you