You enable a proxy using the Edit Data Source pane of a data source. You then select a pre-defined proxy.
To enable a proxy for a data source, follow these steps.
In the Edit Data Source form, expand Enable Authentication, Caching, Proxy, Insecure Access.
Set the Enable proxy slider to On.
Select a predefined proxy from the dropdown list to be used as a connection for this data source.
Click Preview Data Source (optional).
Click Save Data Source.