Launch the app and select your Chromecast device from the list of available devices.
If you can’t find your device on the list, try tapping the “Refresh” button. If the device still does not appear, go to “Why can't I find and connect to my device?” and follow the steps indicated in the article.
You can easily change the selected device after establishing a connection.
To do this, tap the TV icon in the upper-right corner and select another device.
If you don't need to change devices, then tap the “Done” button and continue with the currently selected Chromecast device.
After connecting to the device