Glad to help, I did leave out the aiming.. but you aim it just like the other weapons.
If mobs are close together, most spells will hit the entire mob.
2 Most popular spells:
Wither, damages all mobs in large circular area. (Unlocks at Staff level 4)
Flaming Skull, powerful fireball that has a pretty good range, hits just about anything in its path as far as you can see (well almost). (Unlocks at Staff level 10)
Recommend studying the passive skills instead of throwing lots of points on individual skills.
(typical leveling issues... I dont apply points I dont need until mastered)
Wiki:
Voodoo Staff