विंशोत्तरी दशा, सीधी भाषा में

The Moon at birth has finished some fraction of its nakshatra. The remaining fraction of that nakshatra's planetary years is the balance you are born into. After that, the lords run in a fixed order: Ketu, Venus, the Sun, the Moon, Mars, Rahu, Jupiter, Saturn, Mercury, and around again. The years are the classical ones, seven for Ketu, twenty for Venus, and so on, summing to 120.

A mahadasha is that long period. An antardasha is the sub-period, proportional inside it. The chart page names the ones that contain today's date. It does not narrate the next decade as a plot. A Saturn mahadasha is not a sentence. It is an interval in which Saturn's topics, as your chart actually places Saturn, are traditionally given more weight.

Weight is not doom. People marry, bury, change jobs, and plant trees in every mahadasha, because the dasha is not the only cause in a life and was never claimed to be, by anyone careful.