The most common and most likely answer to this crossword clue is the 2 plus 3 plus 4 plus 5 plus 4 plus 3 plus 12 letter word IF ALL ELSE FAILS READ THE INSTRUCTIONS
I've seen this crossword clue in The Guardian
I
F
A
L
L
E
L
S
E
F
A
I
L
S
R
E
A
D
T
H
E
I
N
S
T
R
U
C
T
I
O
N
S
Buddy explains!
The straight part
We know that "Given suggestion to do manual work" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case given suggestion to do manual work = if all else fails read the instructions.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.