Start company with one thousand hands and some building material (12)
I believe the answer is:
commencement
'start' is the definition.
(synonyms)
'company with one thousand hands and some building material' is the wordplay.
'company with' becomes 'co' (abbreviation. I am not sure about the 'with' bit.).
'one thousand' becomes 'm' (Roman numeral for a thousand).
'hands' becomes 'men' (synonyms).
'and' is a charade indicator (letters next to each other).
'some building material' becomes 'cement' (cement is a kind of building material).
'co'+'m'+'men'+'cement'='COMMENCEMENT'
Can you help me to learn more?
(Other definitions for commencement that I've seen before include "Origin" , "Start" , "Beginning" .)