Closing windows
When you’re done with a window, you can close it with :q or :close.
:q is, of course, the same command that you use to quit Vim. If you have more than one window (or tabpage — more on those later), :q will only quit that window. If there’s only one window :q will exit Vim.
:close does almost the same thing — the only real difference being that it won’t try to quit Vim if there’s only one window open.
Give it a try in the editor. The file that’s currently open is called demo. On the filesystem, there are three other files called foo.txt, bar.txt, and baz.txt. Like before, open some windows to view these files with with :split/:vsplit and try closing them with :q or :close.