Unfortunately, there's no simple answer to your question. The general documentation on using Oracle Cloud DNS Service can be found here. Below is a quick summary of tasks that need to be completed:
- Note the public IP address assigned to your compute instance that's hosting the web server. Assign one if necessary. The compute instance must be on a public subnet to be assigned one.
- In your tenant's root compartment, create a Zone for your domain, e.g. example.com.
- Create an "A" zone record, e.g. www.example.com => 123.123.123.123
- Publish the record.
- On your Registrar's DNS management console, update the name server records to point to Oracle Cloud's name servers assigned to the zone.