Is it that difficult to set up streaming?

Hi folks

My Zoom account is linked to my FB and YT pages, however I find the way to set up a scheduled livestream difficult to understand. Sure, there are the links you can use in the Zoom panel to stream (via the three dots), but if you want to schedule a stream, that's where it gets confusing, at least to me.

That's because on the Webinar In-Session Settings tab for webinars, you can choose between 'Use Zoom web settings' or 'Customize settings below'.  I try to set up the latter - but you can only do it once, so I do it for FB.  That means I can't set up the stream to YT.   Plus the 'Connect video source' indicator on FB remains off. Obviously if there is no stream at that time then it might do that - but I have no way of knowing if the stream will work or not.

Or am I misinterpreting the whole thing?  Is it that I can simply rely on the Zoom web settings - because the 'in-session settings' means that's for the drop down choices within Zoom?

If you could set me straight on this, that would be great - as it's not clear to me how to set up a scheduled stream so followers on FB / YT can mark their interest in advance.