Well if you are new to Diablo III, maybe you should at first run 4x the same class in order to acquire game mechanics when multiboxing...

... Because the difficulty in mixing classes (well it's the part that I like actually) it that you need to know each skill, each rune from each skill, each weapon and armor effect and, more importantly, what it brings to the group.

Of course you don't need to acquire all that by yourself, you can just adapt templates or setup that you see in action on videos, on twitch, on DiabloFans, use D3Planner, etc.