The gates are numbered one to sixty-four, and those numbers are the King Wen numbers of the I Ching hexagrams: the traditional received order in which the sixty-four figures have been arranged for well over two thousand years. Gate 1 is the hexagram called The Creative, Gate 64 is the one called Before Completion, and so on throughout.
This matters for reading the entries in this set, because two quite separate things are in play.
The hexagram is old. Each is a stack of six lines, broken or unbroken, giving sixty-four possible figures. Each carries a name, a judgement text, an image, and line-by-line commentaries, and around them has grown one of the largest interpretive literatures in the world. The material is used for divination and has also been read for millennia as philosophy.
The gate is new. Human Design assigns each hexagram number to a centre in the bodygraph, pairs it with another gate to form a channel, and gives it a psychological reading. None of this comes from the Chinese material. In some cases the modern reading stays close to the traditional one, as with Gate 48 and the hexagram of the Well, or Gate 27 and the hexagram of Nourishment. In others it travels a long way: Gate 11 is the hexagram called Peace, and Human Design reads it as a mind full of ideas.
The two readings are best kept side by side rather than merged. The classical meaning is documented, attributable and old. The gate meaning is documented, attributable and recent. Presenting the second as though it were the first is the most common error in popular writing about this system, and the contrast between them is more interesting than the blur.