Ate in study I’d set up (5)
I believe the answer is:
dined
'ate' is the definition.
(dining is a kind of eating)
'study i'd set up' is the wordplay.
'study' becomes 'den' (I've seen this before).
'set up' says the letters should be written backwards.
'den'+'id'='denid'
'denid' reversed gives 'DINED'.
'in' acts as a link.
(Other definitions for dined that I've seen before include "Ate a meal" , "Had supper" .)