Since you've installed successfully the DataLink server, you have to configure the connection in your Backend Services application. Here
is the introduction to data connectors in our documentation.
The format for Oracle database is the following:
where the database-server-address is your IP.
Please bear in mind that the Data Connectors feature is only available by having the Telerik Enterprise Edition - here is the full description of each license plan - link
Hope that this will help you format the correct connection string.