First the connection with the Light is made in the head of the spiritual Partzuf, where all the calculations take place. Only later do all the decisions that were taken in the head spread in the body and become realized in practice.
In reality there is nothing but a desire. A head is the same desire to receive that in the world of Ein Sof (Infinity) didn’t have a mind, didn’t have a head. It was just a desire to receive.
But later this desire decides that it wants to respond and to answer the Host, the Creator, and in order to do that, it must have a head. In fact, we don’t need anything else but a head!
We repeat the same actions that took place during the spreading of the worlds, the Partzufim, the Sefirot, and the souls from the top down. Now we have to repeat them in the opposite order, from the bottom up, this time by ourselves. So it turns out that our mind, the head constantly grows.
The head grows a little, and then I can do some more with it, it grows a little more and I can do something else. Thus I constantly grow on the spiritual ladder, and my head constantly grows like a cone, until it is equivalent to the world of Ein Sof. This means that now I have thoughts and decisions that encompass all my desires, an understanding and attainment of all the actions.
The actions themselves remain the same. I replicate everything that took place during the descent from the top down and repeat it from the bottom up. But I precede all that by self-calculation, by attainment. Therefore the ascent up the ladder is called the levels of attainment, the ladder of attainment.
Now we are at the bottom of this ladder and behind us there is all of humanity ready to ascend. The only thing we need for that is to increase our mind, the “head” and to start working with the “spiritual head.” Therefore, the knowledge that precedes all the actions is so important.
From the 3rd part of the Daily Kabbalah Lesson 9/8/12, The Study of the Ten Sefirot