Agency workers delayed inside producing patterns (9)

'patterns' is the definition.
(I've seen this in another clue)

'agency workers delayed inside producing' is the wordplay.
'agency workers' becomes 'temp' (I can't explain this - if you can you should give a lot more credence to this answer).
'delayed' becomes 'late' (running late).
'inside' indicates the central letters.
'producing' becomes 'raising' ('raise' can be a synonym of 'produce').
The centre of 'raising' is 's'.
'temp'+'late'+'s'='TEMPLATES'

Can you help me to learn more?