The most common and most likely answer to this crossword clue is the 4 plus 2 plus 3 plus 6 letter word FILL IN THE BLANKS
F
I
L
L
I
N
T
H
E
B
L
A
N
K
S
More clues leading to the result FILL IN THE BLANKS
Buddy explains!
The straight part
We know that "method to complete this puzzle say" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case method to complete this puzzle say = fill in the blanks.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.