Anyone familiar with livestream events on YT? Do they start playing automatically if I have it up on my browser at the scheduled time, or do I need to physically click play at the scheduled time. I'm going to set up a recording program to "tape"

a livestream on YouTube tomorrow, and should be able to schedule my end of it..
Have a funeral service tomorrow for my grandmother, and for multiple reasons I can't be there, and much of my family the same, so they are livestreaming the service. Not only can I not be there, I'll be working and can't watch it live.