This article will guide you on how to configure your Android phone to use google public DNS.
1. Open Settings then press Connections.
2. Press the network that you want to change DNS then press Advance.
3. Change IP settings from DHCP to Static.
4. Locate DNS 1 and type 188.8.131.52
5. Locate DNS 2 and type 184.108.40.206
6. Press Save.