Many yoga postures have slimming effect because they tighten muscles by stretching muscle tissue. For beginners, you can read Zhang Huilan's book Qigong and Meditation. The theories of asana and yoga are introduced in detail. Generally, there are her CDs "Whelan Primary Yoga" and "Whelan Intermediate Yoga" on the market, all of which have clear demonstrations and explanations. I'm a yoga instructor, and these are our study materials.