Emacs is powerful text editor that will automatically open up its own X window if possible or else will simply use the terminal. If you are using X, clicking the left mouse button will position the cursor, as will the keyboard's arrow keys. You can also copy and paste with the first and second mouse buttons respectively, but be aware that pasting occurs at the mouse pointer position, not the cursor position. Under X, emacs also provides a menu bar at the top of the window for some commonly used commands. To start emacs, type emacs filename to edit or create ``filename''. Then position the cursor wherever you'd like and begin typing.
Most emacs commands are either control or meta characters. To type a control character, hold down the control key while typing the character. To type a meta character, press the escape key, release it, and then type the character. I will follow the emacs convention of indicating a control key with a C and a meta key with an M. For example, M-x indicates you should press the escape key and then the x key.
Emacs can be customized with a .emacs file in your home directory.