Big title? Don't worry, anything worth practicing can be analyzed into clearly defined and understandable components. As to whether it is easy to learn to a certain level of standard or perfection is however another issue. Third-eye meditation as its name says is meditation by focusing on one's third eye, physiologically, it is the point between the eye-brows, forming a triangle with the two eyes.
Chapter one of the classic text Taoist Yoga (translated into English by Charles Luk) is on third eye meditation, before going into micro-cosmic circulation. You may wonder how one can do third eye meditation, with such an impressive name, without activating one's primal chi (zhan chi 真氣). Valid question. Chi always needs to go with meditation.
The reason is that in classic Taoist meditation, the first objective is psychological in nature, being called: control your restless mind. Without this objective, the practice will be chi kung for physical health or power. In the old days, students were required to fold their legs and mediate for hours to calm their mind. Those who failed to do so, became restless, would probably give up at this initial stage altogether.
How will a student be instructed to manage his body and mind during this first stage of third-eye meditation? Psychologically, a student will be instructed to control his mind-body to a stage as close to sleeping as possible, without actually having one's head falling down, or jotting. Physiologically, a student will be instructed to let his head drop (which will be counter-balanced by upward chi in a dynamic equilibrium), under gravity, towards his navel (or some will instruct to use his third eye to gaze at his navel). The mind will be concentrated to a single alert-point which keep the mind in a minutest alert [very alert, but minute] state and uses this concentration to generate (or facilitate) chi rises from one's perineum (Sea depth 海底) to one's head, maintaining an erect spine and an almost upright (dropping) head in dynamic equilibrium (downward force of a dropping head vs upward chi force inside the body).
Thus the mind will be highly focused, alert, close to sleeping state, and being controlled. Chi-generation will result, and one feels comfortable and able to proceed further down one's journey of Taoist meditation. In this beginning stage, a student should always keep in mind the respective dangers of lethargy and hyper-activeness of meditation.