Choose the dunderhead's way to roll the dice (6)
I believe the answer is:
decide
'choose' is the definition.
(I've seen this in another clue)
'dunderhead's way to roll the dice' is the wordplay.
'dunderhead' becomes 'd' (head letter of 'dunder').
'way' becomes 'e' (Compass direction - East).
'to roll' is an anagram indicator.
'dice' with letters rearranged gives 'cide'.
'd'+'e'+'cide'='DECIDE'
'the' acts as a link.
(Other definitions for decide that I've seen before include "Resolve or give a judgment" , "Settle conclusively" , "Reach a conclusion" , "Make a judgment" , "Make up one's mind" .)