What to expect when you've finished walking the plank doesn't amount to much (1,4,2,3,5)
I believe the answer is:
a drop in the ocean
'what to expect when you've finished walking the plank doesn't' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'amount to much 14235' is the wordplay.
I cannot really see how this works, but
'amount' could be 'ocean' (ocean is a kind of amount) and 'ocean' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for a drop in the ocean that I've seen before include "It'll have no great effect" , "result of walking the plank?" , "what returning US astronauts may expect?" , "Very little indeed" , "something insignificant" .)