After opening the Administrative Tools/DNS snap in. Right click the Forward Lookup zones folder and choose new zone. | Select primary zone and ensure the store zone in active directory option is checked.
on the next screen choose an option for domain propagation. | Enter your domain name and click next to continue.
Ensure the allow on secure updates option is checked. Click next then finish. | Repeat this process for each domain you wish to use with MintDNS. Unless of course you already have the zones setup etc.