By speaking the incantation and completing the short ritual you are able to rehearse your spells for your next encounter. Once cast, you can select up to two first level spells you know with a casting time of 1 action or 1 bonus action. Once, in the next 24 hour period, when you roll initiative you are also able to cast these two spells at no extra spell slot cost.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, you are able to rehearse up to three spells in this way. The spell slot level required to cast these spells cannot add up to exceed the spell slot used to cast this spell.