set in motion

Start something moving, give impetus to something, as in A press conference set the new project in motion. It is also put as set the wheels in motion, as in Let's set the wheels in motion for the new library wing. This idiom dates from about 1800. It was preceded by put in motion, which dates from the mid-1600s.

The verb has one meaning:

Meaning #1: get going; give impetus to
  Synonym: launch