This is the 2nd video that I'm publishing, this video will show how to get Facebook's RTMP server URL and the key, and how to feed them to the DJI MIMO app on your phone without typing letter by letter (it could drive someone mad...)
NOTE: It might work for you and few days later (or few attempts later) it won't work, that happens when Facebook decides to change a parameter in the key, and in those cases, you'll have to re-copy the enter server URL/KEY from Facebook page to your phone using the method I'm showing in this video.
UPDATE: I have published another video with a very fast fix to this issue, you can see the thread with the video here (https://forum.dji.com/forum.php?mod=viewthread&tid=212863&extra=page%3D1%26filter%3Dtypeid%26typeid%3D696%26typeid%3D696)
The reason I'm leaving this thread is that you'll probably need this method if you want to schedule a live stream (the DJI MIMO doesn't support that).