As you may know there has been a billion reviews saying they don't get it (if a single is equal to a billion) so here's a simple tutorial that will help you get it!

Clicking on the RUN button will put you into this section. You may select any pinned application listed, or you could type it in and click "Run input". To help you remember apps, the apps conveniently use camelCase as the goto id (meaning first word doesn't have a capitalized first letter, the rest do)

And by the way if you don't know how to close it yet, maybe you should be more familiar with the actual windows instead.

Run ID: run

To move windows side by side simply click on the window title.

Running the "ls" app is a great starter to your journey of running apps! It lists a bunch of applications with the "public" key set to true (aka the key that determines if it can be listed or not)

Run ID: run

App List ID: ls

Control panel is how you tweak simple things, like the taskbar color, the window color, and even the wallpaper! It is pinned at the RUN window, but you can enter its id "ctrlPanel" and run it like that

Control Panel ID: ctrlPanel

About Windows 9 ID: about

You should be a little more familiar with windows 9 now. Oh and btw all the apps are js dictionary values in an array