Make extensive use of troops? (6)
I believe the answer is:
'use of troops?' is the definition.
'deploy' can be an answer for 'use' (I've seen this before). I'm not sure about the 'of troops?' bit.
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for deploy that I've seen before include "Place (forces) strategically" , "Move (forces) into action" , "Bring into action sustematically, say troops" , "Put into effective position" , "Spread troops" .)