Ok there are three ways this game's combat system can go:
1.
runescape style: quick turn-based and very boring combat.
2.
fable (and many other rpg's) style: Speed of attack depends on your level, click/press button each time to attack once, and attacks vary in animation.
3.
Somewhat new style: During a battle you go completely first person. Click each time to attack, speed depends on level, animations are slightly varied, and press a button to use your shield/block with weapon whenever you want BUT what sets it apart from #2 you can cast a spell (that you set) by right clicking/pressing other button and when you hold a weapon the way you hold it depends on the weapon. ALSO JUST ADDED, i heard what kenny said and this would include combo's. to activate a combo a player would click again RIGHT after they finish their other attack, if you dont understand try playing pirates of the Caribbean online.