It's not easy being green
There are forty pre-defined charts, and new charts can be created by importing an XML chart definition into a blob field of a new Chart table. If this all sounds a bit too complicated, you can take a look on our book's downloads page at www.teachmenav.com to get hold of a tool to help you create your own charts.
We really intended to write a tool for creating charts, but it seems we're not the only ones to think of this. Rather than try to re-invent the wheel, I've asked Lars Lohndorf-Larsen if we could simply provide a link to his blog post and download.
He said that's fine as long as we make it clear that the tool is not supported in anyway. Here's the link to Lars' blog post.