To start, you first need to add a stage to your event. You can create as many stages as you like.
From the navigation bar on the left hand side of the screen, Go to Settings and scroll down to enable "Advanced Stages". Then, click on the "Save" button.
Go to Manage Stages tab, then click on the "Add Stage" button:
You will be taken to the Create A Stage screen. Give your stage a name and choose "RTMP Livestream"
You can also change the picture of your stage photo, then click on "Create stage".
Once the new stage is created, you will find your stage stream key and RTMP server URL. You'll need these for your third-party streaming platform, so that it knows where to send the content.