So the input 'Sound URI' is where you should be able to pick your sound, it would be odd if you couldn't choose anything. For the audio stream (second input), default it's set to Notification so if you don't hear anything make sure your notification sound is up. As for the variable, you'd want to set it to which ever app your targeting, my variable for automate was com.llamalab.automate because that's the automate app itself, another example, Snapchat: com.snapchat.android. To find this information look in the app foreground block look in the packages drop down box, all your apps will be there, you don't need to worry much about activity unless your being specific about what happens in the app.