A novice, the writer finds an easy task with a small volume (5,4)

'a small volume' is the definition.
The answer and definition can be both quantities as well as being singular nouns.
Maybe there's an association between them I don't understand?

'a novice the writer finds an easy task' is the wordplay.
'a novice' becomes 'cub' (cub is a kind of novice).
'the writer' becomes 'I' (the person who is writing these clues).
'finds' is a charade indicator (letters next to each other).
'an easy task' becomes 'cinch' (I've seen this in another clue).
'cub'+'i'+'cinch'='CUBIC INCH'

'with' acts as a link.

Can you help me to learn more?