Migrating to the Lightning Wire Labs DNS service with already existing zones is easy, as we are providing two ways to import the records.
You may import BIND Zone Files which contain all record data.
An easy way is to import a zone is to transfer it via an AXFR zone transfer and then convert it to a master zone.
This makes the name servers of the Lightning Wire Labs DNS Service authoritative for your zone and you are now able to configure your zone.