How do I use the speakers that are inside the laptop I use to run HA?

I am running HA on a mini PC that has some integrated speakers. How can I use those speakers as an output source in home assistant. When I was running Ubuntu on the mini PC the speakers got automatically detected I i could use them right away but on HA there is no detected device.

No, the speakers are not a separate device, they are literally in the same pc that runs HA

If they can play the music from a browser, they can be run by VLC and this is, what you need.
But maybe there is a need for a Debian driver for the sound deviceā€¦