Quick answer: Open Routing Settings and click on Auto Route.
Changing the Sound Output SourceLiquid Notes comes with a wizard that automatically establishes the routing connections to the most popular DAWs for you when opening a MIDI file. Read more about it in this article http://re-compose.desk.com/customer/portal/articles/1396162.
You may change the Sound Output Source at any time after you have opened a file / project in Liquid Notes. To do so, open the Routing Settings and click the Auto Route-button.
Here is where to find the Auto Route-button:
After you have clicked the Auto Route-button, the Sound Output Source selector window will be displayed. Choose from any of the options there to adjust the routing to your liking.