I have no clue how to use an AED and probably wouldn't because I'm too scared of killing somebody. Especially after that one scene in Breaking Bad where the German guy uses one to off himself. In any case my Target store is literally spitting distance from a hospital so I'll let the people who make $200,000+ a year handle it.
At my last job we had one randomly show up one day (it looked top of the line and VERY expensive) after a couple of employees at a neighboring store collapsed and died while working. They never told us whether or not we were expected to use it or what the policy was, or even if there was a policy, and they sure as hell didn't train us.