Red folding an addition to confusion (12)
I believe the answer is:
complication
'to confusion' is the definition.
(complication is a kind of confusion)
'red folding' is the wordplay.
'red' becomes 'com' (I am not sure about this - if you are sure you should believe this answer much more).
'folding' becomes 'plication' (plication is a kind of folding).
'com'+'plication'='COMPLICATION'
'an addition' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for complication that I've seen before include "aggravation of illness" , "Difficulty" .)