Concisely state position of the kernel (2,1,8)
I believe the answer is:
in a nutshell
'concisely' is the definition.
(I've seen this in another clue)
'state position of the kernel' is the wordplay.
I cannot quite understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'state' could be 'us' (U.S. is an example) and 'us' is found within the leftover letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for in a nutshell that I've seen before include "Brazil's location" , "Succinctly" , "To cut a long story short" , "to be concise" , "Summed up briefly" .)