I don’t really have any beginner guide resources, but I do have these for when you get closer to 70 for you to revisit at that time. I’m trying to “re-learn” SMN since I haven’t played it since around 3.4 in HW, and it’s entirely different now in SB. But here’s the sources I’ve been looking at for level 70 play (for whenever you get there).

This is sort of a generic FAQ; it also has a lot of links to other sources.
This is a basic rotation/opener guide.
This is more advanced, in the event you find you enjoy the job and would like to optimize it for raiding in the future.