Concise set of instructions given to a person about a job, say (5)
I believe the answer is:
brief
'concise' is the definition.
(similar in meaning)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for brief that I've seen before include "brusque > QC, perhaps" , "Summary of facts for barrister to consider" , "Ephemeral" , "Terse" , "Short or concise" .)