How does Conjure Animals work? That seems to be the first time they've even bothered to mention summoning spells.
Conjure Animals
Casting time 1 action. Duration: Concentration (up to 1 hour).
You summon one animal - for this adventure it's a Hunter Shark - and it disappears when the spell ends, if you use an action to dismiss it, or it drops to 0 hp.
It obeys any commands you give it; if you don't command it, it defends itself from hostile creatures but otherwise takes no action.
Acid Splash
Two creatures within 5' of each other make Dex saves or take 1d6 acid damage, with the damage increasing at higher levels.