What does chapter 1 say?
Chapter 1 opens the Tao Te Ching by refusing to define its own subject. It states that the Tao which can be spoken of is not the constant Tao, and that the name which can be named is not the constant name. It then sets out a pair: the nameless as the origin of heaven and earth, and the named as the mother of the ten thousand things. It closes by calling both of these the same in origin and different only in name, and calls that sameness a mystery.
What does it actually mean?
The chapter is not being coy. It is making a specific claim about the limits of description, and it is making that claim first because everything after it depends on the reader accepting the limit.
The argument runs roughly like this. Naming a thing is an act of separation: to call something a river is to draw a line where the water stops being rain and starts being river, and that line is a decision you made rather than a feature of the water. Useful, and not the same as true. The Tao Te Ching opens by pointing out that whatever it is about is exactly the sort of thing that line-drawing destroys, and that a book made of words is therefore a poor instrument for it.
Which raises the obvious question of why there are eighty more chapters. The answer is in the chapter itself: the nameless and the named are called the same in origin. The book is not telling you to stop using words. It is telling you that the description and the thing are not the same object, and asking you to hold the two loosely enough that you keep looking at the second one.
Read this way, chapter 1 is not mysticism. It is a warning label attached to the front of the manual, written by someone who knew exactly how his readers were going to misuse it.
The line people get wrong
The opening is routinely read as “the Tao cannot be described, therefore say nothing about it”, and that reading turns the rest of the book into decoration.
What the chapter says is narrower and more interesting: the Tao that can be spoken of is not the constant Tao. Not that speech is forbidden. That speech produces something different from its object, and that the difference is permanent rather than a failure of vocabulary you could fix with a better word.
The practical difference between those two readings is large. The first one makes the book unusable and rather smug. The second makes it a text you can argue with, which is how it has survived being argued with for well over two thousand years.
One thing to try today
Pick one thing you would describe with a single confident word: a colleague, a problem at work, a mood you have been in since Monday. Write the word down.
Then spend two minutes listing what that word leaves out. Not what it gets wrong, what it simply does not cover. The exercise is not meant to produce a better word. It is meant to let you feel the gap between the label and the thing, which is the gap this chapter spends its whole length pointing at.
Where to read the Tao Te Ching in full
James Legge’s 1891 translation is in the public domain and complete on Project Gutenberg, free and quotable without restriction. If you would rather work through it steadily than read it in one sitting, there is a plan for reading one chapter a day, and Daily Wisdom: Tao spreads the same material across a year at one page a day.