1. Go to the Project menu then Add Track > Instrument Track > UVI > UVIWorkstation (stereo)
2. Create a MIDI Track
3. Choose UVIWorkstation-1-1 as the output for this MIDI track
4. Activate the Multi Record option from the Studio menu - this will add the MIDI input column, which allows you to select your MIDI controller input
4. Activate the Record Enable button then select a preset in UVI Workstation and enjoy!
If UVI Workstation is not listed as a plug-in in Digital Performer, you can read the article UVI Workstation not Showing up in my DAW.