How to exhibit sound in Fortnite?

I have been playing Fortnite with my sister recently, she always wants to play (and fill up) teams and it always annoys me when the strangers start talking (so they have their microphone on) so I wanted to ask if / how to issue it so the one who hears (The other day a baby cried gesch)
I'm already grateful for numerous answers

You have to click on the option button and on the left a window opens with your friends, then you select your team member there and mute the one.

Thanks 😊