We have some documentation here: http://jivesoftware.com/builds/docs/fastpath/latest/documentation/.

It''s out of date, however should help you with what you''re trying to do. As a "hello world" example, I recommend you do the following:
1. create one workgroup on the fastpath tab
2. add yourself to the workgroup
3. log into the group in spark
4. install the fastpath webchat plugin
5. click on the webchat link on the navigation bar in your fastpath tab.

Hope this helps!