Permalinks in Theme 2010

Have an existing site http://www.greenhatworkshop.com and have used default permalinks.

Now want to change to pretty permalinks and cannot get it to work.

Have tried changing .htaccess code an have not been succesful

Have gone to Permalinks, custom and used %postname%, however then when i type in http://www.greenhatworkshop.com/contact the page cannot be found

Have tried Deans Permalink plugin and Custom Permalinks plugin with no luck also.

I am not hugely technical, but can follow instructions well, so please help if you cannot but keep it easy to follow 🙂