Hello,
there is no documentation about the plugin because its purpose is just to consolidate jQuery versions used on a website, when extensions use jQuery extensively, so there are no multiple calls to multiple jQuery libraries anymore. There are a couple links on this website on the download page.
If you just want to add jQuery to your website, you can use this plugin as well. It will just add the proper libraries to your template.
There are a lot of autocomplete jQuery plugins out there, you should try some out before creating your own. You may just find what you need.
To add javascript code without messing up your template, I would suggest this extension: extensions.joomla.org/extensions/edition...ode-in-modules/17122 . It is a great complement to jQuery Easy.

As long as you have the jQuery library included in your template, it will work, yes.