a hand in (something)
A contributory role in something. It was pretty exciting to have a hand in launching the new business. We're going to find everyone who had a hand in this robbery and arrest them.
*a hand in something
and *a part in somethingFig. a part in establishing or running something. (*Typically: get ~ have ~ give someone ∼.) I would like to have a hand in the planning process. I will not let Jane have a part in this project.