In solar arc directions, one starts with a birth chart and moves all planets forward one degree for every year of life to determine the experience of that year of life based on the aspects (angles) between natal planets and shifted planets (progressed planets).
For example, to determine the experience for a person when they are 10 years old, all planets should be moved forward 10 degrees and the aspects between natal planets and shifted planets should be indicative of that year of life.
