Teacher at first request jobs to be done (5)
I believe the answer is:
tasks
'jobs to be done' is the definition.
(I've seen this in another clue)
'teacher at first request' is the wordplay.
'at first' indicates taking the first letters.
'request' becomes 'asks' (I am not sure about this - if you are sure you should believe this answer much more).
The first letter of 'teacher' is 't'.
't'+'asks'='TASKS'
Can you help me to learn more?
(Other definitions for tasks that I've seen before include "Jobs to be done" , "'Jobs, undertakings (5)'" , "charges" , "Pieces of work" , "Labours" .)