Talk notifications help

Good evening, and the first time I use your technical support I ask suca if I am wrong something, I am writing to you about my Cloud: using Talk I cannot understand how to activate the audio notifications and notifications pop up (if they exist) I ask for your help because I am creating a large work community and I would not want to have to communicate with them with another type of app (WhatsApp, Telegram or Messenger).
I remain at your disposal if I have to send you screenshots or anything else to understand how I set it up on my server.
Massimo Marrone