Afterwards take a student to one side (7)
I believe the answer is:
lateral
'one side' is the definition.
(I've seen this before)
'afterwards take a student' is the wordplay.
'afterwards' becomes 'later' (synonyms).
'take' means one lot of letters go next to another.
'student' becomes 'L' (learner, as in L-plates for learner drivers).
'later'+'a'+'l'='LATERAL'
'to' is the link.
(Other definitions for lateral that I've seen before include "belonging to the side" , "Sideways, like creative thinking" , "Edgeways" , "One type of thinking" , "Tall ear (anag.)" .)