There are two birth elements. One is the year you were born. This determines your Ming Gua which is what you use to see how well you match up with the house/office that you live/work in.
The other is for your personal Astrology chart. That involves knowing the day and month you were born. In order to do a proper chart, your hour, day, month and year of birth are required; this natal chart gives you your strengths and weaknesses; as well, it shows the changing qi which occurs every ten years and which influences your life. From this chart, you would have both an element and an animal (i.e., Wood Monkey); each animal consists of one-to-three-three elements. The strength of each element various through the year. Wood is strong in Spring; Metal is strong in the Fall, etc.. At other times, the elements are very weak. All of this is assessed in a chart.