I know of no book that specifically "tutors" you through starting out with SilkTest. Three pieces of advice I would give you:
1. Pick something very simple and begin automating it. For example, Windows Calculator. Take declarations on it. Make it do some calculations. Capture results and compare them to expected results, etc. Use this experience to get familiar with 4Test syntax and logic.
2. Come to this forum DAILY! You will find some serious heavy hitters here. You will get better and quicker answers to your questions here than you will from official Segue support.
3. Make use of the library browser under the help menu. When I first started using Silk, I lived in that library browser. It is better than anything I've seen in any other IDEs.
If you are reasonably proficient with other OO languages and coding practices in general then just skim the sections on test plans, test frames, and designing and coding testcases. These relatively recent interactive-addons are primarily useful for new and inexperienced test programmers. Their downside is that they tend to limit understanding and control.
The real power of Silk lies in it language, object tagging, the class hierarchy and recovery systems. Learn those and you can do almost anything with it.