To configure Mozilla Firefox to run asset and user actions, do the following:
Open Firefox and access this link, which will automatically install the plugin required to run asset and user actions.
Restart Firefox. To ensure that Firefox is fully stopped before restarting, you can open Windows Task Manager (Ctrl+Shift+Esc), right-click the firefox.exe process(es) under Processes and select End Process.
You can check whether the plugin is properly installed by accessing Firefox's Add-ons menu. You can access it directly by using the Ctrl+Shift+A shortcut. You can disable/re-enable the plugin from here as well.