The first thing you should do when you install Roassal is to run the Eassel
World Menu>>Tools>Roassal Easel
And then select the examples, there are lots of examples and all of them includes the code needed to create the visualization. Also there are a really cool examples in the facebook page of Object Profile, but I can't give you the link since in my network is blocked =(.
I'm trying to develop some Twitter data visualizations using Roassal. I want to know if there are a complete list of builders and visualizations that are already implemented which i could use.