"Upload Attachments to a Video or Channel" is a separate feature package and may not be available with your account.
VideoManager Pro allows for the creation of different attachments for a specific video or channel. This makes it much easier to manage your video collection: If, for example, external production companies produce video footage, you can make additional information available for a specific video, such as invoices, licenses, etc.
Depending on what document types your administrator has set up (see section in the administration manual), you can upload file attachments for this purpose, with the option to replace or delete them as desired.