There is just one step:

Copy the file "js/jquery.easie.js" to your project (or the minified version in "build/jquery.easie-min.js"), and you are done!

The syntax is easy.

Either, use one of the predefined, named easings:

$(elem).animate( {top: 100}, "easieEaseIn" );

Or, define your own easing with css3 compatible cubic-bezier parameters:

$(elem).animate( {top: 100}, $.easie(0.25,0.1,0.25,1.0) );

See the web site for more info:

http://janne.aukia.com/easie/