Conclude, when you delve about in (6)
I believe the answer is:
finish
'conclude when' is the definition.
'finish' can be an answer for 'conclude' (I've seen this before). I am unsure of the 'when' bit.
'delve about in' is the wordplay.
'delve' becomes 'fish' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'about' indicates putting letters inside.
'fish' enclosing 'in' is 'FINISH'.
'you' is the link.
Can you help me to learn more?
(Other definitions for finish that I've seen before include "Come to an end" , "curtains" , "Complete (6,3) - See 16" , "surface texture" , "Deal with" .)