Rulebook v2 page: 8
Phase 6: Deployment
Starting with the player who has the initiative, you may cast the spells you assigned to your Spawnpoints (see “Spawnpoints” on page 16). Reveal the spell you have chosen, pay the mana required, and resolve the spell. If you choose not to cast the spell (or if you cannot), it is returned to your spellbook at the beginning of the next Planning Phase.
Playing Hint: Most of the time, you will find that both players can have their Spawnpoints cast spells simultaneously.