Every hexagram is built up in 6 steps, 6 lines. Every line, when changing, turns it (here hex. 1) into another hexagram. In old texts, the place of the lines is referred to as "hexagram 1 its 44" (bottom line) "its 13" (line 2) and so on. Every line is the expression, in the time of hex. 1, of this second hexagram. This hexagram is called the ZhiGua (zhi means its, his, her, and gua means hexagram).
I have put the line texts of hex. 1 and the "ZhiGua" side by side, so it is easy to see the connection. The name of hex.1, Qian, is its entire meaning expressed in one character. But in the image of the lines, it is expressed in 6 images. For every level its own image. The submerged dragon (bottom line) is warned "not to grab the woman". When he appears in the field in the second line he meets his own kin in 13. Timing actions and alertness (line 3) has to do with treading. The uncertainty of line 4 with the clouds not yet giving rainin hex.9. The flying dragon of summer (line 5) with the big harvest of 14. The overbearing dragon with speaking up or breaking through, hex 43.
About the lines and their characters:
For the meaning of Eminent - expansion. Harvest - determination click HERE
According to Shaughnessy (see link 'Books'), the lines of hex.1 describe the positions of the constellation "Dragon" at sunset. Click here for the positions of the 6 Dragons.
Line 1. The winter season is very dry in China, so the dragon is asleep in the water. In spring, when the first clouds appear, the farmers throw 'dirty things' in his pool, in order to get him out and bring the rains. Do not start to sow before you are certain there will be rain! (See the excellent book by S.J.Marshall, 'The Mandate of Heaven')
Line 4. The character 'somehow' can also be translated 'someone' or 'maybe'. 'Dance' is foot + pheasant-feathers: dancing as if flying. Bradford Hatcher (see his book) says: leap/jump yue used to be a shamanic feather dance, a rite of passage, the "leap of faith" from aerodynamic theory to real flight.
Line 6: 'black and yellow': xuan, black, means also mystery. So black and yellow can also mean mysterious or invisible - and shining or visible.
Benefit of 9: all lines changing. Old meanings of yòng, benefit, are related to performing a sacrifice. It is a picture of a bronze tripod.
More about hexagrams 1 and 2 HERE