A text-only interface gives you a terminal window. Keystrokes done in the terminal window are sent to the server, but what you do with the mouse is not sent to the server at all.
One way to use this interface is to edit files on your computer and to transfer them to the server. See transferring files.
You can also edit files in the terminal window, avoiding the need to transfer them back and forth. To do that, you will need to learn a text editor, such as emacs, that works in a terminal window.