User Configuration > Administrative Templates > Microsoft Office 2016 > First Run
User
HKCU\software\policies\microsoft\office\16.0\firstrun
This policy setting determines whether a video about signing-in to Office is played when Office first runs. If you enable this policy setting, the video does not run during Office First Run. If you disable or do not configure this policy setting, a video about signing-in to Office plays when Office first runs.