Make sure you have the exact degree and minute of the Moon between both sunsets, because 10 minutes of Moon's motion will equal to 1 year of life, based on the Chaldean rule of 1 degree = 6 years of life.
Second step: You calculate all the major aspects the Moon will make to the natal chart between these 2 sunsets.
Third step: Of special importance is when the Moon's position from prior sunset progresses to your natal Moon as it will reveal the nature of your Moon by Sign, House and Aspects in your chart.
Right there, you will be very close to the true Natal Chart if you don't know the birthtime.
Fourth step: The Chaldeans also believed that when the Moon moved to a new Moon Mansion was an important year in life as it showed the compulsions, habits, family life going through a re-aligment or new ways of expression.
Firth step: Look also for major aspects to your Natal ASC (personal life, relations) and MC (career, social status) as they will reveal important changes in your life.
Hope this can be helpful,
Ouranos
