Information on the first man (4)
I believe the answer is:
gent
'man' is the definition.
(gent is a kind of man)
'information on the' is the wordplay.
'information' becomes 'gen' (gen can informally mean information).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'gen'+'t'='GENT'
'first' is the link.
(Other definitions for gent that I've seen before include "Toff" , "Informal and short man" , "Auctioneer's tool" , "cove" , "Honourable man" .)