Required: E, N and D, sorted in various quantities (6)
I believe the answer is:
needed
'required' is the definition.
(synonyms)
I cannot understand how the remainder of the clue works.
(Other definitions for needed that I've seen before include "'Lacked, required (6)'" , "Lacked something essential" , "Required; sounds like worked (dough)" , "Was in want of" , "Required, necessary" .)