As much as I love Drupal sometimes the documentation of them or module developers does not have detailed description.
You can do this either by implementing hook_libraries_info() in your module or by providing an info file for your library, which users then have to download. The info file should be in the same format as a regular Drupal info file for a module or theme, and should contain exactly the same keys that are described in hook_libraries_info().
The following example demonstrates the info file of the scrollTo plugin:
title = "jQuery ScrollTo"
website = "http://flesler.blogspot.co.il"
version = "126.96.36.199"
files[js] = jquery.scrollTo.js
The last thing you have to consider is the naming rule for the info file.
LIBRARY_NAME.libraries.info => scrollto.libraries.info
Where your info file needs to be in the main library folder and the LIBRARY_NAME is a subfolder.