Follow the instructions below to do so; 1. Click on your Apple menu, which you will find in the upper-left corner. 2. Click on System Preferences. 3. Select Network. 4. Choose the network service you want to use the proxy with (either Ethernet or WiFi) from the options on the left panel. 5. Select Advanced. 6. Select Proxies. 7. Under Select a protocol to configure, check the box beside Web Proxy (HTTP). 8. Enter the proxy server's IP address and port number on the Web Proxy Server field. 8. Click OK and Apply to save changes.