Another good Wrox book that isn't quite as comprehensive or overwhelming as the one that you are using is the "Knight's 24 Hour Business Intelligence Trainer" book by Brian and Devin Knight. I have always enjoyed their books, presentations and webinars as they make BI concepts really easy to understand.
This book is great for someone just getting into SSAS as it gets a basic cube up and running and then goes all the way out to presenting and slicing data through SSRS and Excel. It also covers data mining, PowerPivot and Performance Point. The focus though is on structuring the data through SSIS loads, fact/dimension concepts and using SSAS. Unfortunately, this book came out after I was already through these concepts. I actually bought it more for the Performance Point and SSRS side. There are now better books out there for these topics as well. However, as a basic, easy to understand overview of all things MS BI, this is a good start.