He had it, then a hotline managed to describe the problem exactly (3,3,4,2,3,4)
I believe the answer is:
hit the nail on the head
'he had it then a hotline managed to describe the problem exactly' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'had it then a hotline managed to describe the problem exactly' is the wordplay.
'it' becomes 'e' ('e' can mean 'electronic' which is similar to 'IT').
'managed' is an anagram indicator.
'to' says to put letters next to each other (I've seen this in other clues).
'describe the problem exactly' becomes 'hit' (I can't explain this - if you can you should give a lot more credence to this answer).
'had'+'e'+'then'+'a'+'hotline'='hadethenahotline'
'hadethenahotline' with letters rearranged gives 'thenailonthehead'.
'thenailonthehead' put after 'hit' is 'HIT THE NAIL ON THE HEAD'.
Can you help me to learn more?
(Other definitions for hit the nail on the head that I've seen before include "as a competent DIYer should?" , "Go straight to the point" , "be spot on, anyway" , "Get carpentry" , "Get the point? Absolutely not" .)