Sundog doesn't output audio on its own, so you need to connect it to a DAW. Basically you set the MIDI Out of Sundog to a virtual MIDI cable, and the MIDI In of your DAW to the same virtual MIDI cable as well (check the preferences in both programs).
Neither Windows nor macOS come with a preconfigured virtual MIDI cable, but it's pretty easy to install one.
macOS: Please follow the guide here: http://feelyoursound.com/setup-midi-os-x/
Windows: Please follow the guide here: http://feelyoursound.com/setup-midi-windows/
The theory is quite easy: You simply route the MIDI notes on different MIDI channels to your DAW. Inside your DAW you connect these channels to different instruments. Voilá!
However, in my experience the setup inside the DAWs can be a little bit tricky. Sometimes it's enough to simply select an input channel from a combo box, but in other cases you will have to select both an input channel and then mark the channel as "ready for recording". In most cases this is symbolized by a small record icon that has to be clicked on all the channels.
Please take a look at the image below to see what I mean. In this example you see Ableton Live. In box 1 I had to select the channels, and in box 2 I had to Cmd-click on all record buttons so that the MIDI notes from Sundog will reach the plugins (box 3).
Important: I highly recommend to set all instrument numbers inside Sundog to "Off" if you work with synth plug-ins! This way the plug-ins will always stay on the preset that you chose inside the DAW and not change their sounds from time to time.
Please make sure that you don't create a nasty feedback loop with your MIDI connections. Your DAW should not send MIDI notes back to Sundog! Otherwise it might happen that these notes will trigger Sundog to instantly send new notes to the DAW as well, and the whole circle starts again.
If you want to use an external MIDI keyboard with your setup you should keep these things in mind:
1) Set Sundog's MIDI In to your external MIDI keyboard
2) Don't use your external MIDI keyboard as an input device in your DAW
Reason: If you use the keyboard in both Sundog and your DAW you will get multiple MIDI note events in your DAW as soon as you press a key. One time from the keyboard itself, the other time when Sundog sends its notes.
Sundog can send MIDI sync signals to your DAW. This way the DAW will start and stop if you press play / stop in Sundog. Please make sure that your DAW supports the "MIDI Clock" standard if you want to use this feature. "MMC" or "MTC" (other standards) won't work!
I try to give specific instructions for popular DAWs in the FAQ. However, there are some DAWs that don't have trials (e.g. Logic Pro X) or need a dongle for the testversion (e.g. Pro Tools). In these cases you will have to consult the manual of your DAW on your own, as I can't take a look at them.
I hope this small guide was useful! If you have further questions you can contact me here. And if you could provide specific instructions for a DAW I haven't covered yet I'd be really happy to hear from you!