A way to find their meanings
The hexagrams in a pair are the upside-down of each other, like eg 43 and 44 (see image above). For hex.1 and 2 this is the same, even though it is less visible. Hex.1 is the upside down of hex.1, and hex.2 the upside-down of hex.2. So hex.1 and 2 are not one, but two pairs.
The two hexgrams are each others 'Qian gua': reflected hexagram, like in water.
The consequence of 'upside down' is, that lines 1 and 6 in a pair must have some kind of related meaning. In hex.1/1 the dragon hides until it is time to come out. In hex.1/6 the dragon refuses to pull back. In 1/2 the dragon comes out down below, in 1/5 it flies high up. In 1.3 the Junzi (who acts like the dragon) acts according to the moment, in 1.4 he dares to deal with the unknown.
Then there is the 'relating line', called the fanyao. Hex.1.1 changes into hex.44/1. There are two fanyao and two qianyao in the image above.
There is also another connection: with (the lines in) the complementary hexagram. This is a very different relation: they are each others opposite, or rather each others contrast.
Hex.1/1 the dragon abiding its time vv hex.2/1 the warning that time will not wait for you. Hex.1/2 the dragon appearing and learning vv hex.2/2, nature which is what it is, does not come forth but 'does without doing', and has no need to learn anything.
Mirror grouping 01.1-01.6-43.6-44.1 (above): observing the laws of your actions
Mirror grouping of 02.1-2.6-23.6-24.1 (below) Using the right base for motivations
Mirror grouping 01.2-01.5-13.2-14.5 (above): Observing the codes in relations
Mirror grouping 02.2-2.5-07.2-08.5 (below): Doing without doing - respect in relations
Mirror grouping 01.3-01.4-09.4-10.3 (above): Being master of emotions and decisions
Mirror grouping 02.3-15.3-02.4-16.4 (below): Being (true to) oneself in emotions and decisions