Boy carrying bananas, came up with another fruit (6)
I believe the answer is:
damson
'another fruit' is the definition.
'damson' can be an answer for 'fruit' (damson is a kind of fruit). I am unsure of the 'another' bit.
'boy carrying bananas came up' is the wordplay.
'boy' becomes 'son' (synonyms).
'carrying' means one lot of letters go next to another (in a down clue, the bottom letters carry others).
'bananas' becomes 'mad' (slang for insane).
'came up' is a reversal indicator (I've seen 'come up' mean this).
'mad' back-to-front is 'dam'.
'son' after 'dam' is 'DAMSON'.
'with' is the link.
Can you help me to learn more?
(Other definitions for damson that I've seen before include "Stone fruit for nomads" , "Dark purple plum" , "Wild plum" , "Small stone-fruit for nomads" , "jam producer" .)