This plugin is very simple, so this readme doesn't need to be very long. Basically, it just gives you access to a new shortcode that will allow you to easily inject anchor links (<a name="my-anchor"></a>) into your content using a shortcode (so it can be edited without having to view the source of the page). Here's how you'd create an anchor inside your content.
[anchor id="my-anchor"]
And that's it. Now you can create a link anywhere else in the content of the page and just link it to #my-anchor and that link, when clicked, will move the user to whatever position on the page you added your anchor.