Instruct the class (5)
I believe the answer is:
order
I believe this clue is a double definition.
'instruct' is the first definition.
(to instruct is to give orders)
'class' is the second definition.
(I've seen this in another clue)
'the' acts as a link.
(Other definitions for order that I've seen before include "Uniformity or fraternity" , "One may be tall if demanding" , "Jesuits, say" , "Tidy state - that's a command" , "architectural style" .)