Here are the steps to make an event’s album private so guests can upload content but cannot see anyone else’s uploads:
Open the event editor.
From the Events page, tap Create New Event if you’re setting up a new event, or tap the Edit icon beside an existing event.
Navigate to the Privacy & Security section.
In the event editor, tap Next until you reach the Privacy & Security tab.
Enable Private Album.
Locate the Private Album toggle switch and tap it to turn it on. A note explains that guests will be able to upload photos and videos, but they won’t be able to view any of the uploaded content.
Save your changes.
Tap Save to apply the private album setting. Your event’s album is now hidden from guests, while still allowing them to contribute their own photos and videos.