Visit the activation website specified on the yur screen (eg, https://activate-apple.com/. Follow the on-screen instructions on the activation website and enter the activation code displayed on your Roku device.
To reset a forgotten password, unlock your account or recover an Apple ID visit https://i-forgotapple.com/. An Apple ID is the personal account you use to access Apple services like the App Store, iTunes Store, iCloud, iMessage, the Apple Online Store, FaceTime, and more.