To use Google Cast on an Android TV, simply follow the steps below:
Step 1: Ensure that both your phone/tablet and Android TV Box are connected to the same Wi-fi network
Step 2: Download the Google Home app on your phone/tablet
Step 3: Open the Google Home app and click on the cast icon on the upper right corner to be directed to the Device page
Step 4: Select "MIBOX" to connect your phone to your Android TV Box
Step 5: Enjoy casting by simply clicking on the cast icon on your apps
Please note that the Cast devices and your Android TV must be connected with the same Wi-Fi network.