Live broadcast is a unique camera mode available on the Samsung Galaxy Note 5 and Samsung Galaxy S6 Edge +. This feature allows you to perform a live streaming session on YouTube using the Camera of your smartphone.
Make sure your phone is connected to the internet (mobile data or Wi-Fi), the launch the Camera app and switch to video recording mode. At this point you can either choose the front-facing or rear (main) camera. Tap on Mode > Live Broadcast and follow the onscreen instructions. In the Sign-in to YouTube window, tap on the Sign-in button and enter the email address and password associated to your YouTube account. Live broadcast requires access to your basic profile info and YouTube account, tap on Ok to accept the app permission. At the end of this procedure you should be able to broadcast content to your YouTube channel.
If you are unable to sign-in to your YouTube account, the following website offers a workaround: https://9to5google.com/2015/08/21/how-to-fix-galaxy-note-5-s6-edge-youtube-live-streaming-already-enabled-error/