NOTE: See also our CSS examples which contain many "interactive" effects
In general you will need the following ...
There are lots of free jQuery libraries and scripts, with their accompanying CSS, available on the web (including this page). Most jQuery needs some CSS, therefore don't forget to grab any CSS (files) which accompany the jQuery documents/examples you download.
You can either link .js documents to your page or add the scripts to the head or body tags, but you will need to read the individual licensing agreements for usage. Some are free, others require payment.