By default, your collection is set to be “Public.” This means it's available to everyone under "Collections" in the main menu of the On-Demand player. Here's how to hide a Collection Menu by changing it to “Private."
From your Dashboard, click the On-Demand “Collection Menus” link.
Click the collection you want to make private.
Under the collection menu title, click the “Settings” tab.
Click the “Edit” button in the “Playback Options” section.
Toggle the "Visibility" button to “Private” and click "Save."
Now when you preview your On-Demand player, the collection won't appear under "Collections" in the main menu. You can still embed private collection menus on a web page.