Here are important steps that should be followed the very first time you use the app.
The very first step, like in most audio software, is to select the audio device and channels you'll be using. For that, go in the Tools > Options menu, and there select the correct device for both input and output audio.
Secondly, as Swar Performer is mainly for Midi playback, you'll need to select any Midi devices you plan to use. At the bottom of the Audio Settings dialog, you will see an "Active Midi Inputs" list. Check any device(s) there.
Once done, select the Midi Devices tab, and there you can do further configuration:
Once that is done, click on OK to close the Options dialog.
By default, Swar Performer is configured to target SwarPlug, but you
may want to use any other virtual instrument. You may also have nice
audio effects plugins that you want to include as well. So for them to
be visible in the app, you need to run the Tools > Scan Plugins
option, click on Options and then scan the the plugin type you want. You
can run this again with a different plugin type if needed.
Once that is done, you should be good to start using the software.
The app should run the first 30 days in trial mode, but if you have purchased it, this might be the right moment as well to activate it fully with the serial number you must have received by email.
Select the Help > Activate/Deactivate menu option, and then enter (or copy/paste) the serial in the field of the Activate dialog. Press OK and your software should be activated.