Just a LITTLE beginner Guide for you...I try to make it as easy as I can do...
1. Start WoW
2. Log in to your toon
3. Start HB (NOT WHILE THE LOADING SCREEN,RIGHT AFTER)
4. Select your bot (Questing for you,cause u want to quest...)
5. Select your Profile (Kicks lvl profile maybe?)
6. Turn on Azenius Plugin,AutoEquip2 and Talented (any other Plugins are optional
7. Select your Talent-Build by mark the Plugin and select Shadow-Priest/Select your Weapon Style!
Simple is that?!
OF COURSE you can change to grind,change your CC etc.
In addition I recommend the Software "ARelogg" or "HBRelogg"(which is the same I guess) Tutorials are in the Forum!