Confuse students about working at public library originally (7)
I believe the answer is:
'confuse students' is the definition.
'nonplus' can be an answer for 'confuse' (synonyms). I'm unsure of the 'students' bit.
'about working at public library originally' is the wordplay.
'about' is an insertion indicator.
'working' becomes 'on' (on can mean working or activated).
'at' means one lot of letters go next to another.
'public library' becomes 'PL' (abbreviation for public library).
'originally' becomes 'nus' (I can't explain this - if you can you should believe this answer much more).
'onpl' going into 'nus' is 'NONPLUS'.
Can you help me to learn more?
(Other definitions for nonplus that I've seen before include "Cause dismay" , "State of confusion" , "Perplex totally" , "Perplex, confound" , "Flummox" .)