Joomla Instruction
Here are some useful links
Video Tutorials
There are a series of 20 lessons for the Joomla 2.5 tutorial, but the first 10 you can probably skip, although you could check them out to give you background.
Here is the link to lesson 11, http://www.youtube.com/watch?v=HP7jmEaWww0
The meat of what you need is in lessons 13, 14, and 15.