Get the Stadia app
The Stadia app allows you to easily manage your Stadia account, set up your Stadia Controller, make purchases, and play games directly on your Stadia-compatible phone (only on supported devices). The Stadia app is available for most smartphones.
On your Android phone, download and install the Stadia app from the Google Play Store.
Note: Minimum requirements for the Stadia app can be found here.