Dear me, there's this branch in the river! (3)
I believe the answer is:
arm
'branch in the river' is the definition.
'arm' can be an answer for 'branch' (synonyms). I'm not sure about the 'in the river' bit.
'dear me there's' is the wordplay.
'ARM' is hidden in amongst the letters.
However, I'm not sure how this is indicated.
'this' is the link.
Can you help me to learn more?
(Other definitions for arm that I've seen before include "Limb or branch" , "Activate fuse" , "Prime" , "Activate warhead" , "Steel" .)