Putting together of new gable a mess (10)
I believe the answer is:
assemblage
'putting together' is the definition.
(thesaurus)
'new gable a mess' is the wordplay.
'new' is an anagram indicator.
'gable'+'a'+'mess'='gableamess'
'gableamess' is an anagram of 'ASSEMBLAGE'.
'of' acts as a link.
(Other definitions for assemblage that I've seen before include "collection is made" , "Group" , "congregation" , "Collection (of things or people)" , "Collection, gathering" .)