The following procedure will help you to configure IPFIX on a vDS and enable it on a dvPortGroup:

1. Connect to vCenter Server using the HTML5 client and go to the Networking inventory view.
2. Select the desired vDS, go to Configure | NetFlow, and click EDIT...:

3. On the Edit NetFlow Settings screen, specify the details request and click OK:

4. Once you're done, you can now enable NetFlow on the desired dvPortGroups:

This completes the process of enabling NetFlow on a vDS.