As per the following diagram, we are going to add a new child domain to the rebeladmin.com domain tree:

The name of the new child domain will be europe.rebeladmin.com. This will still be under the same Active Directory forest. Similar to new domain tree, the child domain and parent domain will have two-way domain trust created automatically. This domain controller is going to be the first domain controller on the child domain, therefore it cannot be a RODC.