User Configuration > Administrative Templates > Microsoft Project 2016 > Project Options > Interface > Project Guide settings for 'Project1'
User
HKCU\software\policies\microsoft\office\16.0\ms project\options\interface
Choose whether the side pane displays the default Project Guide or a custom Project Guide your organization has developed. If you enable this setting, the Project Guide you specified will be displayed when the Project Guide is opened. If you disable or do not configure this setting, the user's default setting is used.