Inaugurate, set in motion (8)
I believe the answer is:
initiate
This clue is a double definition.
'inaugurate' is the first definition.
(I've seen this before)
'set in motion' is the second definition.
(I've seen this in another clue)
(Other definitions for initiate that I've seen before include "Begin or admit into a closed society" , "Cause (action) to begin" , "Cause (process) to begin" , "having special knowledge" , "Admit with rites into a society" .)