Minions work in a few different ways. By default, they just follow you around and attack random things in your Demigod's area. Alternatively, you can control them, usually as a group.  This is where hotkeys come in.  "I" will select only your unique Demigod's minions, in Oak's case, his spirits. "N" selects your Demigod and all minions.  "M" selects all of your minions, but only your minions.

You can lets say, move Oak to a flag, but hit "M" and move all your minions behind you, if you would like to pull them off of the front lines.  Or you can charge them in at an enemy and hang back.  To recall your minions from the map in any area, the "O" hotkey will tell them all to come back and follow you again.  Hope this helps you a bit.

It will take a little practice, but minion control isn't that bad... but does require some work, as minions have tiny brains and are rather stupid when left to decide things on their own.

yes,  the standing order for minions is to follow your demigod around and attack things in the area. 

But they can selected independently and controlled like an RTS.  There are hotkeys to select each type of minions.  I = unique, 8,9,0 for minotuars, seige archers, and priests respectively.

Also, M selects minions, H selects Demigod, N selects everyone.

I don't find much use for moving individual minion types independently, however moving your group of minions independently from your Demigod is very important to general gameplay.   When I play generals, my hand always hovers over M and H.  You need this independence to set up things like pinches, kiting, and dancing.  And to be able to run with your hero while attacking with your minions.

It's a great game, and Oak is fun to play.  The learning curve is not small.  Good luck.