I have to follow summary relating to breakdown (9)
I believe the answer is:
digestive
'relating to breakdown' is the definition.
I can't tell whether this definition defines the answer.
'i have to follow summary' is the wordplay.
'i have' becomes 'I've' (contraction of 'I have').
'to follow' says to put letters next to each other (some letters go after or follow others).
'summary' becomes 'digest' (I've seen this before).
'ive' after 'digest' is 'DIGESTIVE'.
Can you help me to learn more?
(Another definition for digestive that I've seen is " Type of biscuit".)