I'm using Terminal.app version 2.9.1 which is built into macOS. I just learned that I can split the screen vertically using Command + D (and un-split it via Command + Shift + D).
However, I do not understand how to use the two views differently. In fact whenever I type a command in the lower screen, say
ls, the same happens in the upper screen.
Also, I do not understand how to use the upper screen. I read somewhere that Command + Alt + ↑ should do the job, but that doesn't seem to work.