I use what I find helpful and don't worry too much about other stuff.
The way I learned it was to jump in for NaNo (using the 30 day trial) and just kept writing and finding stuff as I needed it.
I do now know how to set up my styles beforehand, but don't worry because I generally put it to Word before publishing anyway, and I have to re-do/check all the styles from scratch ('cos, styles are a [curse]).
I like creating new scenes and either keeping them separate by part (easier to do the word count by scene, chapter, part), and the ability to 'remove' all the text and stick it in a 'notes' folder down the bottom for later perusal (when I realise it was a mistake to wipe out the whole mountain).
However, I am working my way through a short, online course (at your own pace) just to see if there's something that may be of value and I currently don't know about it (found one).
It's Australian, but don't know if that makes a difference ...
2 Hours to Scrivener Power | Australian Writers' Centre
It's the same place that does the once a month Furious Fiction competition.
However, as I haven't finished the course (a hand in plaster makes it interesting), I can't say whether it's worth the money or not.