Finishes 6 down with right and left (5)
I believe the answer is:
sides
'right and left' is the definition.
(I've seen this before)
'finishes 6 down' is the wordplay.
I cannot quite see how this works, but
'down' could be 'd' and 'd' is present in the answer.
The remaining letters 'sies' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
'with' acts as a link.
Can you help me to learn more?
(Other definitions for sides that I've seen before include "Outer edges, left and right" , "Takes the part of someone in a dispute" , "opponents?" , "More than one team" , "Angles" .)