He starts with its bestsellers (4)
I believe the answer is:
hits
'bestsellers' is the definition.
I can't judge whether this defines the answer.
'he starts with its' is the wordplay.
'starts with' suggests taking the first letters (I've seen 'start with' mean this).
The initial letter of 'he' is 'h'.
'h'+'its'='HITS'
Can you help me to learn more?
(Other definitions for hits that I've seen before include "welcome in the theatre world?" , "The sort of strikes" , "Raps - successful recordings" , "Pop successes" , "that please the public?" .)