Young Samuel, you are, they say, A-1 Japanese warrior (7)
I believe the answer is:
samurai
'japanese warrior' is the definition.
(I've seen this before)
'young samuel you are they say a-1' is the wordplay.
I cannot quite see how this works, but
'you' could be 'u' (commonly used in online communication) and 'u' is located in the answer.
'are' could be 'a' (short for 'are', historical unit of measurement) and 'a' is located in the answer.
'a' is found in the answer.
'1' could be 'i' (Roman numeral) and 'i' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for samurai that I've seen before include "military type" , "Sudoku variant" , "Member of Japanese warrior caste" , "Former Japanese military caste member" , "Traditional Japanese warrior" .)