For anyone else who, like me, hasn't done anything with webcasting using the church's Webcast 3.0 and you don't have a Teradek device and don't know where to start, here are a few steps that the previous users have assumed you knew and skipped over:
1) Go to https://webcast.churchofjesuschrist.org
2) You can get help there on getting started, but one thing you will need to do is click on the "Teredek" button and add a new device. Yes, you don't have one, but that's OK. Just click the button, name it "phone" or something like that and leave the rest blank/default and click add.
3) Now you can schedule an event. Select "phone" as your teredek device
4) After it is scheduled, the meeting will show up on your dashboard. At the top right is a gear that says "setup" click it and go to "Other setup". Here you will find the RTMP URL and stream name.
5) Proceed with the other instructions on this page.
NOTE: I'm still experimenting and trying to get this to work, so if I've said something wrong above, I'm hoping someone else who knows more about it than me will correct me. Thanks!