How does voice chat work in fortnite?

I play fortnite on the Nintendo switch and I don't know how to use voice chat can someone help me?

Put in the headset, put it on and speak.

You have to go into the settings first before you simply connect the headset. In the settings there's such a sound sign that you click and then ideally "open microphone"! Not "push to talk"! Then you can still adjust the volume.