You can perform any Sorcery effect, regardless of whether you know the right Schticks, if you find some source of the magic. This can be an arcane tome or ancient magical object, you can study how another sorcerer works similar magic (in combat this takes a full Sequence of nothing but observation, out of combat it takes a minute or so), you can be taught by a mentor or otherwise learn how to perform each specific effect. This knowledge lasts only one story.
You can study another player character sorcerer (or friendly NPC companion) in this fashion at a cost of one Magic point per effect.
You can use this skill with your Magic default for Sorcery. You may have to spend a host of Magic points to stand a reasonable chance of success.