Open the command prompt and type ipconfig to find your machine's IP address (more info).
Make sure your laptop and your phone are on the same Wi-Fi network.
Open your React Native app on your device.
You'll see a red screen with an error. This is OK. The following steps will fix that.
Open the in-app Developer menu.
Go to Dev Settings → Debug server host & port for device.
Type in your machine's IP address and the port of the local dev server (e.g. 10.0.1.1:8081).
Go back to the Developer menu and select Reload JS.
You can now enable Live reloading from the Developer menu. Your app will reload whenever your JavaScript code has changed