After you have added your Managed domain to DNS Made Easy, you will want to add the same zone as a secondary zone in NSONE.
1. Click on 'zones'
2. Click on 'Add zone'
3.Add in your zone name and select 'Secondary Zone'.
In order to retrieve the Primary IP information, click on the domain in question in DNS Made Easy and navigate to the "Name servers" tab after you have created your 'Transfer ACL (AXFR)' and Applied the 'Transfer ACL (AXFR). Save the IP for AXFR transfers provided by DNS Made Easy (18.104.22.168). This IP must be added to the 'Primary IP field' on NSONE's interface.
You are all set! Your backup option has been configured and your domain availability is higher to the public!