Could someone explain how to make a split view?

Could someone explain to me how you can create a split view?

I've been following the tutorial on the guides section but that doesn't even want to build, so I scratched that one.

I feel that the tutorials and guides section is a bit half-assed, as if it's incomplete and gives little depth on how to actually do something. (This could be just me though since I'm autistic)

If anyone could give me an example that would be awesome.

Thanks in advance.