First design of ateliers (8)
I believe the answer is:
earliest
'first' is the definition.
(I've seen this before)
'design of ateliers' is the wordplay.
'design of' is an anagram indicator (I've seen this in other clues).
'ateliers' anagrammed gives 'EARLIEST'.
(Other definitions for earliest that I've seen before include "Soonest" , "Original or most previous" , "Arriving first" , "With the least delay" , "Next available" .)