The emacs tutorial included with the editor is good enough to wean you off the mouse, for the most part. You can be productive after that, and you don't even need to open to another window. The startup page might show the hotkey combination for loading the tutorial, depending on the version of emacs.

There's other documentation included with emacs beyond that, e.g. the info pages. Anything that can be read from within emacs has the added advantage of helping you get used to scrolling and moving around inside buffers (again, hopefully without the mouse).