Either game, works the same way.
select the person you want to have that spell, select the spell so that it is in one of the first 2 magic slots. Then highlight that slot when back on main screen. I would then just go to each "person" and click on them. I liked BattleHeal spell the best for this. That should do it..if they don't need healing, it doesn't cost you any mana.
Same with summoning..select the caster, then the spell to be in one of the first two slots. Highlight that "magic" on the character sheet and cast. Instead of using a sword, he would be using that spell. Make sure your mana is high enough.
The creature called should fight, mine did..but it really only helped me out with things were a bit hectic