1. Run Firefox.
2. Click "Tools" from the menu bar.
3. Click the "Options" menu item.
4. Click the "Advanced" icon at the upper right side.
5. Click the "Network" tab.
6. In the "Connection" field, click "Settings..."
7. Select "Manual proxy configuration:"
8. Enter the proxy's IP address in the field "HTTP Proxy"
9. Enter the proxy's port number in the field "Port"
10. Check the box "Use this proxy server for all protocols"
11. Click OK.
12. Click OK.
13. The first website you surf to, you will be prompted for your username and password.