If you've started ladish for the first time, you should:

 1. Create a new studio (in the menu, Studio -> New Studio)
 2. Configure JACK (in the menu, Tools -> Configure JACK)
 3. Start the studio (in the menu, Studio -> Start Studio)
 4. Start apps (in the menu, Application -> Run)
 5. Connect their ports by click & drag on canvas
 6. Save the studio (in the menu, Studio -> Save Studio)