I'm also new to Sourdough. I started playing with it this weekend and it's pretty nifty. I found the docs available on the sourdough site quite adequate for getting up and running. The API documentation is very thourough and I recommend you look at it for trying to figure out what each component wants to do.
Installation:
http://sourdough.phpee.com/index.php?node=10
Getting Started:
http://sourdough.phpee.com/index.php?node=11
Database Abstraction Guide:
http://sourdough.phpee.com/index.php?node=4
API Documentation (Wahoo!):
http://sourdough.phpee.com/api/
If you have specific questions, ask them and perhaps I, or someone else, can answer them. I cannot stress enough how helpful it is to have well documented source code. It's too uncommon in open source projects these days.
P.S: If you're dissatisfied with the template systems available with sourdough, you are of course free to use other ones. Sourdough isn't tied to a template engine. I am starting to really like Savant, so I created a Sourdough wrapper for the Savant library which I have started to extend a little as well.