Comment 12 for bug 1902378

No, we have only one global enable state. This means when we enable broadcasting on start, all enabled connections will connect.

I think it is better to add a checkbox below:
"Turn on Live Broadcasting when applying these settings"

This is defined here:
https://github.com/mixxxdj/mixxx/blob/1ca77e00a53bbd63e5bb899ac27b8897efa95200/src/preferences/dialog/dlgprefbroadcastdlg.ui#L124
And used here:
https://github.com/mixxxdj/mixxx/blob/1ca77e00a53bbd63e5bb899ac27b8897efa95200/src/preferences/dialog/dlgprefbroadcast.cpp

ui files can be edited with the QtDesigner.

But the first step is to build Mixxx from source.
https://github.com/mixxxdj/mixxx/wiki

Than you should read through this:
https://github.com/mixxxdj/mixxx/wiki/Bugfix%20Workflow