Between each round a so-called Directive Panel pops up. Here you can select options for your characters. You can use 3 levels of Anger, Power (mana usage) and Aid and you can also select Flee, Parley, Berserk and Commence.
Depending on your settings, your party member will be more or less fierce and considerate. Peeps with higher aid setting tend to heal/buff themselves and party members or debuff enemy more reliably. They can even raise friends. This makes combat slower, but you have a bigger chance to win. Mobs don't use resurrection.
Attacks and healing (and some other actions) generate or mitigate aggro. You can have an affect on aggro generation with equipment too.
The directive panel can be hidden to automate combat. Berserk does that as well.
While the directive panel is active, you can invoke the character sheet and equip/unequip stuff or use other items like summoning a creature using a wand, or drink a potion. Summoned creatures disappear as soon as the combat ends.
On top of the standard archetype actions, there are some special ones like: Take Risk, Feint, Dust In The Eye, Coup de Grace, Shield Bash, Shield Blocking, Personal Tactical Traits, Encourage, Annoy, Shake-off, Incite, Discipline
Their occurrence also depends on directive settings. You don't need to micromanage this process.