What it is
Chaturvimshamsha divides each sign into twenty-four equal parts of 1°15′. Its count starts from only two signs: Leo for odd signs and Cancer for even signs.
How it is calculated
Rule: in an odd sign the first part is Leo, in an even sign Cancer; then onward in order, so the zodiac turns twice across the 24 parts.
Example: a planet is at Aries 17°. 17 ÷ 1.25 = 13.6, so the fourteenth part. Aries is odd, so the fourteenth sign from Leo: Virgo (a full round of twelve from Leo, then Leo, Virgo). In D24 the planet is in Virgo. At Taurus 17° it would be the fourteenth from Cancer, that is Leo.
What tradition looks at in it
Parāśara links the chaturvimshamsha to learning. Tradition looks at Mercury (understanding and language), Jupiter (knowledge) and the lords of the 4th and 5th houses. It gives a glimpse of the kind of study the mind enjoys, for example subjects involving numbers, language or deep reflection.
How much the birth time matters
On average the ascendant moves about 1 degree every 4 minutes; some signs rise faster, some slower. One part of D24 is 1°15′, so a difference of roughly 5 minutes in birth time can change the D24 ascendant. The Moon crosses one part in about two and a quarter hours. In your chart, ePandit shows next to every varga how many minutes of birth-time change would shift its ascendant. A five-minute error is common, so read the D24 ascendant only with a reliable time.
How to read it calmly
Read D24 as a second look, not a verdict. Tradition first studies the 4th and 5th houses and their lords in the main chart (D1), then the running dasha. D24 only helps check whether the same theme shows up here as well. A planet's sign in this varga decides nothing on its own. A child's education is shaped by interest, effort and good guidance; do not let a chart become pressure on them.