1. Open the settings app on your device

2. Navigate to the WiFi settings. It might be named "Network & Internet" or "WiFi" (It can differ from device to device).

3.  Click the Wi-Fi tab to view all WiFi networks 

4. Press the WiFi network you are connected to or click the information I icon or the settings cog if that appears. (It can differ from device to device).

5. Click the edit icon in the top right or click "Advanced Settings" until you see a section for "Proxy".  (It can differ from device to device).

6. Set the type as Manual for the proxy if prompted.  The other details can be left as they are. The details are below:

Server / Hostname: surfprotect.exa-networks.co.uk

Port: 3128