Herb's right - it's not so difficult (7)
I believe the answer is:
simpler
'not so difficult' is the definition.
I can't judge whether this definition defines the answer.
'herb's right' is the wordplay.
I cannot quite see how this works, but
'right' could be 'r' (common abbreviation) and 'r' is found within the answer.
'herb' could be 'simple' (simple is a kind of herb) and 'simple' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'it's' is the link.
Can you help me to learn more?
(Other definitions for simpler that I've seen before include "More easy" , "That wasn't so hard!)" , "Easier" , "Less complicated or complex" .)