Android How VPNService commuicates with Internet

I am trying to create Android sample vpn app.

I am created VpnService by referring to https://developer.android.com/guide/topics/connectivity/vpn#java

VpnService.Builder builder = new VpnService.Builder();

// Create a local TUN interface using predetermined addresses. In your app,
// you typically use values returned from the VPN gateway during handshaking.
ParcelFileDescriptor localTunnel = builder
    .addAddress("192.168.2.2", 24)
    .addRoute("0.0.0.0", 0)
    .addDnsServer("192.168.1.1")
    .establish();


<service android:name=".MyVpnService"
         android:permission="android.permission.BIND_VPN_SERVICE">
     <intent-filter>
         <action android:name="android.net.VpnService"/>
     </intent-filter>
</service>

The VPN service starts. But when i try browsing Google or some other url. It fails to load? Can someone explain me

.addAddress("192.168.2.2", 24) what is this address ==> This creates TUN interface

But how this TUN interface will communicate with Internet.?