Need some help set up a speaker

I’m running HA supervised on a Debian box, all the IoTs run on a VLAN which also includes an Ubuntu box attached to TV and used as a media player.

I’d like to attach a speaker to the Ubuntu Box and be able to send text-to-speech notifications (or play pre-recorded audio clips) via speaker as part of HA automatons. I’m guessing some setup must be required on Ubuntu box for this functionality.

Can anyone point me to a good tutorial or explanation to set it up?

Using what software as media player?