The way live streams work is that you create a live stream “container” which you can place on your website or share with people.
Whenever you send a video feed to that container, it will be live, so you can just start and stop a video feed to that live stream whenever you want, and anyone with the link can see the actual video whenever you are live.
This also means that you can create a live stream container now and only stream to it in the future, thus “scheduling” the stream ahead of time.
I hope this helps, and let me know if there’s anything else I can help with!