For a start, take the tube back to the end of the road (5)
I believe the answer is:
debut
'for a start' is the definition.
(debut is a kind of start)
'the tube back to the end of the road' is the wordplay.
'back' shows that the letters should be reversed in order.
'to' means one lot of letters go next to another (I've seen this in other clues).
'the end of the' says to take the final letters.
The final letter of 'road' is 'd'.
'tube' in reverse letter order is 'ebut'.
'ebut' after 'd' is 'DEBUT'.
'take' is the link.
(Other definitions for debut that I've seen before include "Start -- launch" , "The coming out of a society girl" , "where one began" , "Tubed (anag.)" , "entrance" .)