Backing, put a pound on for her (4)

'her' is the definition.

'backing put a pound on for' is the wordplay.
'backing' says the letters should be written backwards.
'put' means one lot of letters goes inside another.
'a pound' becomes 'L' (the pound sign is based on an L).
'on for' becomes 'aon' (I am not sure about this - if you are sure you should believe this answer much more).
'l' placed inside 'aon' is 'alon'.
'alon' written backwards gives 'NOLA'.

Can you help me to learn more?