Here's an example retrieving top 30 investors in Air Canada as of 01-Apr-2019.
ek.get_data('AC.TO',['TR.InvestorFullName', 'TR.PctOfSharesOutHeld', 'TR.SharesHeld', 'TR.HoldingsDate', 'TR.SharesHeldChange'], {'SDate':'2019-04-01', 'EndNum':'30'})
I think you would benefit from looking at this tutorial, which talks at length about metadata discovery (finding field names and parameters) for use with Eikon Data APIs.
Thanks so much!
Is it possible to loop this code over several monthly dates, from 2019-04-01 to present?