Internet Security

Why install Avast Internet Security if I have Avast Free and Windows Firewall?
thanks,

Because it offers a lot more protection levels than avast free + windows firewall.
https://www.avast.com/compare-antivirus

I have Avast Internet Security. Do I have Safezone and DNS? How can I know if they are enabled? Thanks.

Check the installed components.
control panel > software > avast > change > change

Is this the control panel in Windows or Avast? If they are installed but disabled, how can I enable?

Avast 2015: Change, add, or remove individual program components https://www.avast.com/faq.php?article=AVKB96#artTitle

avast support and FAQ https://support.avast.com/support/home

Videos
https://www.avast.com/faq.php?q=video&authenticity_token=LcpaVtlJ8rTppkucz%2FyFBZWWSh5VfzUbszrGpfWjoXg%3D#searchForm