Arrived, having done away with small monikers (4-5)

'monikers' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'arrived having done away with small' is the wordplay.
'arrived' becomes 'came' (come can mean to appear or arrive).
'having' indicates putting letters inside.
'away' is an anagram indicator (letters move away from their original places).
'with' means one lot of letters go next to another.
'small' becomes 's' (abbreviation - e.g. clothes size).
'done' anagrammed gives 'oden'.
'came' enclosing 'oden' is 'codename'.
'codename'+'s'='CODE-NAMES'

Can you help me to learn more?