Slitherine

I can add a general - but how does one place a unit under a different generals command?

You can only do this in deployment, but select the unit, hover over the general you want to assign the unit to, open the menu you would for movement and actions and you should see a button to reassign command to that general.

Once a unit is part of a general's command, you can move the general to that unit should you desire. Command groups are locked once battle begins, though you can still move around a general who isn't in melee combat between units within his command group.

thanks
I'll do that next time.......