To add push notifications to an Android app, developers can use the Twilio Notify API and ngrok to forward traffic from their server to the app. First, they need to create credentials for their backend server using the Notify Console, then configure their backend using Node.js and ngrok. Next, they need to set up their Android app by adding dependencies in the build.gradle file and registering a Broadcast Receiver and Service classes. They also need to implement a class called BindingResource that uses Retrofit to bind directly to their backend application. Finally, they can test their app by sending push notifications from their server using the notify.js script. With these steps, developers can turn their app into one that provides users with timely information and updates.