Hi and welcome,
Launchkey is a MIDI keyboard, not a synthesiser. Do it sends MIDI data.
Add an Instrument track, and select a VSTi, which you want to use. Use your MIDI Keyboard to send the MIDI Notes. The VSTi will make the sound. In the Devices > Device Setup > VST Audio System, select the ASIO driver, you want to use (your Audio Device). Here you will hear the sound.