First of all, you're missing an R in the title. And if it is the last one you are missing, well, that's not good.
AARRR is a nice conceptual schema for organizing activities-- I don't really see it is as something that is "applied", as much as a reminder that: a) each of the five areas is important in its own right, b) each of the five areas has separate goals, and c) each of the five areas has separate metrics.
At least, that's the way I'm using it.