Resources about relaxation training as used in CBT
As I mentioned previously in the comments, there are a wide range of relaxation techniques which can be used within CBT.  Having not read the book mentioned, I looked it up and found how the relaxation technique was described in the book.

From this I can tell you that the technique you have been taught is called Progressive Muscle Relaxation [PMR] (McCallie, Blum, &amp; Hood, 2006).

PMR involves the process of feeling the muscles in your body relax starting from one end of the body to the other, noticing the difference in sensation whilst also listening to your slow deep breathing.

You can obtain plenty of free or paid for PMR scripts (also known as screeds) through searching on Google.

References

McCallie, M. S., Blum, C. M., &amp; Hood, C. J. (2006). Progressive muscle relaxation. Journal of Human Behavior in the Social Environment, 13(3), 51-66.DOI: 10.1300/J137v13n03_04