GDQuest has a good tutorial about using an Events Bus, but it's only in GDScript, so if you're using C# it'll probably be less useful.
I can't send links, but a quick Google search of "Godot NPC schedule system" yielded several high quality resources, including a video where someone implements an Animal-Crossing-style schedule, and info on Stardew Valley's schedule system.
If you're super new to programming in general, I'd suggest you take a look at GDQuest's free Learn To Code From Zero lessons. (I'm not affiliated with them, I just find them really helpful, and their tutorials are how I got started.)