To access your FTP, you must first generate your login credentials. To do so, go to Owner profile/FTP access on the left side navigation menu and click "Reset FTP password". This will generate your username, password, port, and URL for logging into your FTP.
To connect, you must have a third party FTP client, Kinkbomb recommends FileZilla.
Once you have uploaded files via FTP you can import them into your library by going to Product/FTP uploads.