If you are trying to include audio from multiple sources, such as music from a media player on top of your microphone, then you would need to use an audio mixer to combine the audio together and create a single input device that can be selected in Studio. For Windows computers, you can use audio mixing software such as VB Audio Cable.
How to install a VB Audio Cable
Download VB Audio Cable from the download page.
Unzip the downloaded file.
Run VBCable_Setup.exe or VBCable_Setup_64.exe, step through the Wizard and reboot once you're done.
Once it's installed, VB Audio Cable can be selected as the output option for the audio you wish to include.
How to include audio from a media player
If you want to include audio from a media player, you would need to select the CABLE Input (VB-Audio Virtual Cable) as the audio device within the media player or software where the audio is being played from.
Then, select VB Audio Cable as the "Input" option within the Restream Studio.
How to combine microphone with other audio
If you want to capture Microphone audio along with the other audio, you'll need to adjust the Microphone listen settings to output to VB Audio Cable.
Go to your System > Sound options and select "Device Properties" for your microphone.
Next, click on "Additional Device Properties".
Then, click the "Listen" tab.
Check the box for "Listen to this Device". Then, choose CABLE Input (VB-Audio Virtual Cable) as the Playback through this device and select "Apply".
Now both audio playback from the media source as well as microphone audio will be included in the Restream Studio!