How to use a proxy in Firefox?

@percy_bauch 

To use a proxy in Firefox, follow these steps:

1. Open Firefox and click on the menu button (three horizontal lines) in the top-right corner of the window.
2. From the drop-down menu, click on "Options" or "Settings."
3. In the Options/Settings preferences tab that opens, scroll down and click on "General" on the left side menu.
4. Under the Network Settings section, click on the "Settings" button. This will open the Connection Settings window.
5. In the Connection Settings window, select the "Manual proxy configuration" option.
6. Enter the proxy server's IP address or hostname in the "HTTP Proxy" field. If the proxy server requires a different port number, enter it in the "Port" field.
7. Optionally, if you want to use the same proxy for all protocols (like HTTPS or FTP), check the box for "Use this proxy server for all protocols."
8. If your proxy requires authentication, tick the box for "Use this proxy server for all protocols" and enter the username and password in the respective fields.
9. Click on "OK" to save the changes and close the Connection Settings window.
10. Finally, close the Firefox options/preferences tab.

Your Firefox browser is now configured to use the proxy server you specified.