Is Split View working for anyone?

Read the release notes. It explains it in detail.

I had to read it, it's trocky to explain.

People: read the documentation

Split View

You can now put two windows in a full-screen space. These windows may belong to the same application or two different applications.

There are two ways to create a split-view space. First, you can long-press on the green full-screen button of a window that supports full screen. Place the first window on one half of the screen, then choose a second window from an exposé arrangement of eligible windows.

Alternatively, you can drag a window that supports full screen up through the menu bar to open Mission Control. In Mission Control’s Spaces Bar, you are given an option to create a new full-screen space. You can then select a second window and drag it on top of the full-screen thumbnail to create a split view.

Window minimum sizes are respected, so you are only able to combine two windows if their combined minimum widths fit within the width of the screen.

Once in a split-view space, you can drag the divider between the two windows left or right to resize them. You can drag the toolbar of either window to the other side to cause the two windows to swap sides.