Left-click sends minions towards the direction you're facing. Multiple clicks sends multiple minions. Holding the button sends all your minions (one by one).
Right-click calls back minions. Multiple clicks calls back multiple minions. Holding the button calls back all minions (all at once).
Holding left and right mouse button sends all minions towards the direction you're facing. Hold the left and right button while moving your mouse left and right to guide your horde around. Move the mouse back and forward to move them closer or farther away from you.
Holding shift locks the closest target in front of you. Holding shift while using your mouse buttons will send your minions to that target.
Alt is used for magic. Shift and alt can be used to lock on a target and use magic on that target.
Q enables you to place a guard flag at the location of your minions, or yourself, I'm not really sure (only used it once). You can move your horde around using right and left mouse button and then Q to drop a guard flag where they are. You can lock onto the guard flag (shift) and send minions with the left mouse button to guard that position.
I'm only a couple of hours into the game, so that's all I know for now. I did play the first game, however, and I recommend you do too, because something tells me you haven't.
Hope that helped. Also, I'm not English so forgive my spelling.