How to configure DNS zone for domain
1. In case of DNS zone for domain is managed by your service provider, please ask them to point MX record for domain to host mx.inbox.eu. Optionally You may would like to set A record for mail.your_domain to point to mail.inbox.eu. Instruction can be found here.
* If DNS zone fo domain is trasfered from other provider, then it is nesessary manualy back up records, that has not assigned automatically (for example, A records, instruction here)
If you were unable to find answer for your question, please write to firstname.lastname@example.org