You can read about it in a book, but the reality is that the skill can't be mastered without putting the hammer and nail in your hands.
Training requires placing the nail cautiously and carefully on the wood, in the appropriate location, while carefully balancing the nail in one hand. It requires feeling how much pressure it takes to lift the hammer and then adjusting your hand and arm to the motion required, analyzing the weight needed to lift the hammer, and then gauging the force needed to connect with the nail, all while using your eyes to see exactly where to place the hammer onto the nail so that you don't hurt yourself or those around you.
That's how we teach ultrasound. We place the tools in your hands, while helping you advance your critical thinking skills, so that your mind and body can adjust to what it takes to know how to perform and even master the intricate skill of ultrasound.
There's more to learning than opening textbooks.
The books are important, but what matters most in the field of ultrasound, and in medicine, are the HANDS ON skills.