Instructions Ken discovered inside garden ornaments (7)
I believe the answer is:
genomes
'instructions' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'ken discovered inside garden ornaments' is the wordplay.
'discovered' means to look at the middle letters (dis-covered - outer letters removed).
'inside' is an insertion indicator.
'garden ornaments' becomes 'gnomes' (I've seen this before).
The middle letter of 'ken' is 'e'.
'e' placed within 'gnomes' is 'GENOMES'.
Can you help me to learn more?
(Another definition for genomes that I've seen is " DNA sequences of organisms".)