How does logistics automation work?

Recently I've been involved in a lot of discussions around automation at my job, almost all of which have been centered around transporting material around the factory.

I understand the theory behind it, as in, a dispatch system handles where material is meant to be transported to, sensors detect if the material is in the right place, and so forth. What I don't understand is how this is actually done on the transport side.

Assuming a single conveyor from point A to point B, any material can follow the path and end up at the destination. In a non-linear system, a material may go from point A to point D, point F to point B, etc, all utilising a single central line.

The system doesn't have to necessarily detect obstacles or navigate around an open area, as from all the demonstrations I've seen, the systems are fixed rails/conveyors, so there is no complex AI involved from what I understand.

If this was time-based, then I'm sure it would introduce a world of error if the line stopped for any duration, so I'm guessing each vehicle is sent with information that signals to the line that a diversion is needed.

I'm aware the solutions each automation company have to this are their own, but generally speaking, is there some kind of common technique to achieve this?

My questions are:

1. How is this done from an engineering point of view?
2. How does the system ensure that the material reaches the right destination?
3. How does the vehicle branch off from the central line while others continue along the path?
4. What information is provided to the vehicles and how is this handled in the system/at the destination?

I'm hoping I've over-complicated this in my head but as I've been more involved in talks around this, I've become fascinated in it and would love to learn more.

Not sure if I used the right flair as this is kind of a combination of Mechanical and Computer, but hopefully this is the place to ask regardless.