10. Emacs Manipulate Files
In a lot (if not all) of Emacs documentation, you will see the syntax C-[letter]. This just means hit the Ctrl-letter, but for shorthand purposes, we'll call Ctrl with C. If you see syntax such as M-[letter], that means use the Meta key, most commonly the Alt key.
C-x C-s - Save a file
C-x C-w - Save file as
C-x s - Save all
The save file options will prompt you if you want to save each file.
Opening a file
This will prompt you to type a filename to open. If you do not have a file that already exists, it will create a new file. You can load up a directory as well.
Play around with opening files and saving files.
What command is used to open a file?