To change these preferences on your Mac:

Choose Apple menu > System Preferences, click Network

Select a network service in the list on the left hand side, (e.g. Wi-Fi) and click Advanced

click Proxies

Tick the Web Proxy (HTTP) Box and enter the Address and Port number (see https://bitznpcz.com/supportdesk/kb/faq.php?id=2 for the school settings)

Click on OK to save