The Sun hand moves around the clock face in a 24 hour period following the natural movements of the Sun over an entire year. The anticlockwise direction is the direction of the Sun in Winter while looking North where the Sun rising in NE and setting in NW is anticlockwise as viewed from the Southern Hemisphere. The opposite is true if you live in the Northern Hemisphere while looking South which is why clockwise is the norm for standard clocks.
In the centre of your timezone the Sun is at its highest point at 12noon only at 4 points of the year, the rest of the time the Suns highest point can be almost 15mins ahead or behind the mean time set by your watch. The difference you see on a simple sundial and the standard mean time we follow today.
Moving away from the centre of your timezone to the edges can also add 30mins difference to the sundial time and standard mean time often with daylight savings time added for good measure.
For this reason the numbered dial is not fixed but moves to accommodate your position in the timezone and natural changes in the Suns postion throughout the year so the sun hand continues to point to the correct mean time we know as correct local time.
The Sun Image moves to the end of the hand during the peak of the Summer months and returns to a low point on the hand in Winter by following the green circle of the Earths Ecliptic set as the difference in the Earths tilt to its orbit around the Sun. Moving the Sun from the blue outer circle of the Tropic of Capricorn to the blue inner circle of the Tropic of Cancer. The red circle between is the Equator the Sun crosses during Spring and Autumn.
The Green Ecliptic ring is divided into 12 equal sections labeled with the signs of the Zodiac. In modern Astronomy Aries is the first 30deg arc or 0 to 2 hour of Right Ascension(RA) around the Celestial Equator with Pisces as the last 30deg of arc or 22 to 24 hour of Right Ascension(RA). The 0 point is set by the Suns position on the Celestial Sphere when the Sun crosses the March equinox on the Earths Equator. This fixes the Zodiac ring to the Earths seasons before being projected out as a way to pin point objects in the night sky. This is fine over small time periods but axial precession of Earths poles will see them circle the stars over 26,000 years adding drift to the stars recorded positions.
A good example of this is the Southern Cross known by the Ancient Greeks as Crux, where Ptolemy regarded them as part of the constellation Centaurus. They remained entirely visible as far north as Britain in the fourth millennium BC before axial precession moved them ever closer to the Celestial South pole of today.
Modern Astronomy is now using The International Celestial Reference System (ICRS) where the 0 point is fixed among the stars using the measured positions of extragalactic sources (mainly quasars) removing the Earth as a reference point. As a start point of J2000 January 1, 2000 it was as close as 15secs Right Ascension(RA) to the Zodiac start point but will drift away from the Zodiac with the removal of Earths axial precession on its fixed position.
While the Sun will take a Year to circle the Green Ecliptic the Moon will do it in 1 lunar month passing over the Sun as a NEW MOON before returning to the opposite side as a FULL MOON.