1. Download Stremize app at https://stremize.com/download or enter 8300665 in the Downloader app on Android TV (Firestick, Chromecast, Onn.)
2. Open the app and log in or create a Stremize account.
3. Go to Profile → Active Key in the settings menu.
4. Enter your activation code.
5. Tap Activate → Your Premium plan will be unlocked.