How on earth do I use my companions optimally?

Hi! First time playing thru BG3. I'm still in Act 1, Im a lvl 4 wood elf paladin, and I feel like I'm not using my companions to their full potential. For one, I really have no idea how to use Wyll or Astarion in combat. I think I've learned how to use everyone else pretty well, but I just can't seem to figure out their usage in the party? Any tips going forward?