Hi @Postie. You would need to download the official and latest version of the Ring App from the Google Play store directly for Android devices. If you’re not able to access the Google Play store on your device, then you would not be able to download the official Ring App which is needed in order to set up and use your Ring Doorbell.
You can try contacting our support team directly as they can take a better look at what’s happening and determine if the phone you have is compatible with the Ring App. Please give our support team a call at one of the numbers available here. We’re taking additional steps to protect our team and help reduce the spread of COVID-19, so this has resulted in longer than normal wait times. If you are outside of the US, please read our response to COVID-19 here to see how to contact support.