Hello, For that Triumph you need to go on Patrol and cast a super from all Elemental subclasses. So fill your super bar and use that super then switch subclass. You need to do every Arc, Void and Solar before returning to orbit.

Could you elaborate on what your issue actually is? In the video you linked, the triumph you show has nothing to do with what you showed in your subclass listing by moving around one subclass's subabilities.