SAS
I think it's EASA this week, but no-one is really sure.
Not sure about rules as such, but the regulations for licensing specify what is to be taught. The how bit comes from where you get taught. Some of the bigger schools have practice notes for their FIs/CFIs(e.g. Bristow).
In the wider world, practice can vary a bit more. I have met CFIs/FIs who don't teach it for PPL (and likely at all), seeing it as an "advanced manouvre" as opposed to preventative and emergency training; some who just let the aircraft fly a little bit itto it's own vortices at height then recover without allowing the incipient element to begin; some who aggresively put the TTP way below the horizon in the belief that you get more airspeed more quickly that way; others who teach auto as the way to get out. On the whole, though: most seem to do more or less the same, allowing the incipient state to begin indicated by a sudden ROD acceleration, then put the disk at the horizon, maybe lower the lever a bit, wait for indicated airspeed then pull pitch again to recover.
The point about type is may be important. Most civi training is done on light piston aircraft. In an earlier discussion, it was said that the lighter the machine, the lower the ROD required to get into VRS due to the relative masses involved. Following this, the incipient indications will develop with less loss of height in lighter machines. And this probably extends to the required height to recover.
TT