I'm going to make a couple assumptions as you didn't provide much information to go on.
1. You have just started chapter 1.
2. You are trying to run the tests from chapter 1.
You first need to download and install the software for the book. (
http://www1.idc.ac.il/tecs/software.html )
The first several chapters all use the hardware simulator. Take a look at the hardware simulator tutorial included on the software page. Also, I highly recommend the Hardware Survival Guide written by Mark. (
http://tecs-questions-and-answers-forum.32033.n3.nabble.com/Hardware-Construction-Survival-Kit-tt3385741.html )
In general, you run the hardware simulator (I used HardwareSimulator.sh on my mac.), load the .tst file for the chip you are working on, then run it. The .tst file will load the .hdl file and the .cmp file and run the tests, reporting on the output.
If this is not clear, or you have more questions, please let us know.