"I'm new to the software and would like to broadcast (using) Shoutcast ... How do I do it?"
You use the "Internet Broadcast" plugin and configure it to use your Shoutcast (or Icecast) server.
https://www.playitsoftware.com/Plugins/View/InternetBroadcast
To start with use "PlayIt Live Main Mix" as your source in the plugin as that avoids various possible problems.
Google translate gives:
"Você usa o plugin "Internet Broadcast" e o configura para usar seu servidor Shoutcast (ou Icecast).
https://www.playitsoftware.com/Plugins/View/InternetBroadcast
Para começar, use "PlayIt Live Main Mix" como sua fonte no plug-in, pois isso evita vários problemas possíveis."
Carlos Santos
Sou novo no software e gostaria de transmitir no Shoutcast... Como faço?