Player is fitted with new style of boot (6)
I believe the answer is:
oboist
'player' is the definition.
(oboe player)
'fitted with new style of boot' is the wordplay.
'fitted with' means one lot of letters goes inside another.
'new style' becomes 'is' (I can't explain this - if you can you should believe this answer much more).
'of' indicates anagramming the letters (the answer comes from or 'of' the letters).
'boot' with letters rearranged gives 'obot'.
'is' put within 'obot' is 'OBOIST'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for oboist that I've seen before include "Do I boost the musician?" , "Instrumentalist" , "orchestra member" , "Musician who plays woodwind of treble pitch" , "Wind player" .)