A class given instruction (5)
I believe the answer is:
order
I believe this clue is a double definition.
'a class' is the first definition.
(I've seen this in another clue)
'instruction' is the second definition.
(an order to do something)
'given' is the link.
(Other definitions for order that I've seen before include "Symmetry" , "It could be the usual" , "One of Great Lakes" , "One may be tall if demanding" , "association" .)