Synthesizer V Studio automatically recognizes audio devices and audio outputs connected to the computer. The audio device may be selected when multiple devices exist.

In the Audio section of the Settings panel, set the output device you're going to use.
The Pro version allows the use of MIDI devices such as MIDI keyboards.
See "Using a MIDI Keyboard" for details.
Synthesizer V Studio Pro comes with VST・AU・AAX plugin versions, which can be used within DAWs that support virtual instrument plugins.
Please refer to "Linking to DAW with plugins" for details on setup with the plugin version.