Hi there. Prismatic will allow you to use a specific Stasis and a specific Strand super, an aspect, a grenade, and a melee ability from each. You need to complete several missions launched from the old tower in the Pale Heart after completing the campaign to unlock those on your Prismatic subclass. To get the dedicated Stasis and Strand subclasses themselves, their aspects, fragments, and abilities requires completing the Beyond Light and Lightfall campaigns like normal.