To enable subsequently the FireWall module you have to perform a change installation of Avira Antivirus.
- Click in the lower left corner of your desctop the icons Windows → Settings.
- Click Systems → Apps & features → Avira Antivirus → Modify.
- Click Yes to accept the User Account Control request.
- Select the "Modify" option and click Next.
- Select the “Windows Firewall” checkbox and click Next.
- The Windows Firewall module will be added to your Antivirus.
- Restart your system to use the new added module.