If one googles for zhan zhuang, one can easily find what the form is like. And it has been called different names, such as horse stance, standing like a tree or embracing a tree. That's why even without a teacher one can learn how to practice the form. For relaxing the mind, some find it easy, some find it more difficult. Traditionally, teacher and students didn't need to worry about the mind. Why? Because students were expected to stand for as long as it takes to calm down one's mind, which in practical terms, it might mean sweating all over! So, that takes care of the mind, if one really wants to (or needs to).
I mentioned in previous posts that one key concept is to have a pair of stretched hands. Why is it necessary? And why is it that a practitioner be advised to relax body and mind but with the hands stretched? And why in a relaxed state, the teacher will ask a student to stand until he is so tired that his mind becomes relaxed?
A key chi-concept is involved here. It is called "Points stretched with body relaxed" (點緊身松). I can't stress more about the utmost importance of this concept.
Chi is like electricity. It can only be generated and cultivated through difference in energy level, in Tao-lingo, the setting up of a field with yin and yang components. Specifically, the stretched hands are high-energy points whereas the rest of the body are low energy points; and chi can thus be created and made to move. Why relaxed mind is important? Because if our mind is wondering, our thoughts will attract chi which will be made wondering following our fantasy! On the other hand, when the mind is focused to "look at", "listen to" or "experience" (all metaphors) this energy difference of the body (i.e. points stretched, body relax") chi will be generated inside the body. In short, chi follows the mind, and different energy level inside the body will cultivate the chi thus focused.
There are two additional axillary concept to be applied:
1. Stretched but not being stiff (緊而不僵)
2. Relaxed but not being collapsed (松而不懈)