A minor branch, you understand (4)
I believe the answer is:
twig
This clue could be a double definition.
'a minor branch' is the first definition.
'twig' can be an answer for 'branch' (twig is a kind of branch). I am unsure of the 'a minor' bit.
'understand' is the second definition.
(I've seen this before)
'you' is the link.
Can you help me to learn more?
(Other definitions for twig that I've seen before include "Finally understand" , "Only a minor branch" , "bit of wood" , "Division of branch" , "Slender woody shoot" .)