My Shadowheart just got Level 2, so all she has is low level spells. At higher levels, it looks like you have to go into the spellbook and choose the new ones. I am still trying to figure out how the spell slots thing works ... how do you know how many active spell slots you have left? Eventually the whole list of icons grays-out when you use them all, except for cantrips. I have to un-learn the system I was used to seeing, & stare deep into the Mists of the Unknowing.