To active a DNS server:

1. Go to Services / DNS, check on activation checkbox, set forwarding servers(optional) and click apply.
   
2. To create a local domain, go to Local domains menu and click Add.
   
3. Set the name to domainname and description and click add.
   
4. To add sub-domains or entries, select your domain and click add button.
   
5. In the next screen, check on sub-domain checkbox and set sub-domain name. Check on internal / external checkboxes, select type of entry and set the target. Click add button to create your sub-domain.