Like so many medieval Chinese manuscripts, this is written very tersely. Unless you already know virtually all this material you will not be able to make much sense out of the text. Having said that, this text is actually much easier than many others.
This is not a general book about Taoism, or Taoist philosophy, or even about putting Taoism into action. It is a reference book on a most difficult and demanding type of meditation & energy exercise called 'internal alchemy' whereby one achieves spiritual immortality. This information was considered very secret and the style of writing made sure that the wrong people got this book they couldn't learn the secrets without a teacher.
Here is one of the more easily understood passages from the text:
"Nowadays when Taoists speak of pumping the bellows, they do not mean pumping a bellows; they mean tuning true breathing. If you know the furnace and cauldron but not the bellows, then yin and yang are separated; even though furnace and cauldron be set up, they are useless. If you know how to pump a bellows but not how to tune true breathing, then you're missing the essential subtlety whereby the pumping is done. How will you snatch the wholesome energy of heaven and earth to crystallize the elixir?"
It may seem as if the above is taken out of context, but it is not. I'm assuming this is a lecture given to advanced students pointing out that while they have done all the necessary steps they are missing the key aspect of the technique.
If you know enough to understand this book, it would be incredibly valuable. And compared to many other ancient Chinese texts I find this one does explain a great deal, so far it is the most accessible of these cryptic books that I've found.