The first composer to go (6)
I believe the answer is:
travel
'go' is the definition.
(I know that go can be written as travel)
'the first composer' is the wordplay.
'the first' becomes 't' (1st letter of 'the').
'composer' becomes 'ravel' (Maurice Ravel).
't'+'ravel'='TRAVEL'
'to' acts as a link.
(Other definitions for travel that I've seen before include "Movement from one place to another" , "tour" , "Journey from one place to another" , "Varlet (anag.)" , "Make a journey" .)