American's note was put up in school library (4)
I believe the answer is:
bill
'american's note' is the definition.
'bill' can be an answer for 'note' (synonyms). I'm unsure of the 'american's' bit.
'put up in school library' is the wordplay.
'put up' says the letters should be written backwards.
'in' says the answer is hidden in the clue.
'llib' can be found hidden inside 'school library'.
'llib' backwards is 'BILL'.
'was' is the link.
Can you help me to learn more?
(Other definitions for bill that I've seen before include "Parliamentary draft of proposed law" , "Note - police - invoice - list" , "parliamentary proposal" , "Banknote; beak" , "Bird's beak or statement for payment" .)