For testing things, try the SandBox.
For a quick look on what Wiki is, check out OneMinuteWiki.
For a guideline on good working habits with wiki, see WikiEtiquette.
If you run Microsoft Windows, then probably you want to take a look
at WindowsInstall for more tips.
For all of the Wiki markup features, see TextFormattingRules.
The WikiRPCInterface might interest you if you're into scripting.
WikiAttachments - very useful things.
WikiVariables - putting things on top of other things.
JSPWikiPlugins - The documentation on plugins.
JSPWikiFAQ - A list of some frequently asked questions.
MultipleWikis - If you want to run multiple Wikis using the least amount of effort.
JSPWikiTips may help you a bit.
To see what this particular wiki is about, click on the Wiki name
on the top left corner of the browser window, or click here.
Good luck, and thanks for choosing JSPWiki!