In simple words
In Vedic astrology your life moves through nine long chapters called dashas, always in the same order. Which one you start in depends on your Moon at birth.
The Sun dasha lasts 6 years. While you are in it, Sun's themes colour those years. Your chart page in Vedic mode shows which dasha you are in now, with dates.
Themes
The Sun period lasts six years and highlights identity, authority and purpose. You may step into leadership, deal more with figures of authority or feel a strong drive to be recognised for who you are.
What it supports
Confidence, leadership, public roles, connection with mentors or parents, and clarifying your direction.
What it asks of you
The Sun asks for integrity and humility alongside confidence. Shine without burning others, and let your purpose guide your choices.