Grew up a Christian in predominantly Hindu country so you can’t escape the influence of their world views. The belief is based on the concept of a soul and Karma. It’s a long discussion but to keep it very short the objective of each one of us is to purify our soul by doing the right things ( karma and dharma ) which can be a challenge given that we have been given free will and are also driven by our sensory needs. At the end of one’ bodily life on earth the soul is not pure and ready to become one with the almighty, then based on karma the soul is born again.
Based on Vedic astrology which derives the chart based on date and time of birth and location. The astrologist are able to drawn up a chart that allows them to tell the life of the person in consideration. His likes and dislikes. Their mental and spiritual attributes and on and on. I have experimented with this myself and have been shocked as to what the astrologer was able to tell me things about myself and my family.