Question regarding streaming

Hello, I've been recently streaming on my youtube channel. I still don't know how to figure out putting a sound in game via stream-labs application.

The rest might be okay, by the way I'm on my headphones. How do I fix it and what do I do?

https://i.imgur.com/pLwW7JS.png

I asked Chatgpt, I'll try to figure this out. All the help is welcome.

Why not use OBS? Works fine for me.

need to add audio sources desktop and mic (if you have one) if you have a cam with an integrated mic use that also start with default obs stramlabs is good but its also bad for starting bad habits