There is no "book of Enoch." We have several collections of ancient Jewish writings that commonly go by 1 Enoch, 2 Enoch, and 3 Enoch. I assume you probably came across 1 Enoch or one of its writings since the other two are much less known outside of scholarship? I will offer an introduction that leads into your questions.

1 Enoch is collection of five writings from the Hellenistic and early Roman Imperial periods. They are (roughly) the Book of the Watchers (1 Enoch 1-36), the Parables of Enoch (1 Enoch 37-71), the Astronomical Book (1 Enoch 72-82), the Animal Apocalypse (1 Enoch 83-90), and the Epistle of Enoch (1 Enoch 91-108). While dating remains debated, especially since these writings have incredibly complex composition histories, the Astronomical Book is generally regarded as the earliest (4th to 3rd centuries BCE) and the Parables of Enoch the latest (1st century CE?). The Book of the Watchers is commonly dated from the late 3rd century to the middle of the 2nd. You can access basic introduction to these texts in many places. George Nickelsburg, Jewish Literature Between the Bible and the Mishnah: A Historical and Literary Introduction (2d Ed; Minneapolis: Fortress, 2011) is a classic introductory source.

Each of these writings is in some way what we refer to as revelatory literature. As in, the contents of the writings are framed or presented as coming from revelation given by the Jewish high god to a human recipient, with lower-level deities (often designated as "angels") often mediating the revelation. Four of these writings are examples of what scholars refer to as an Apocalypse, which means a revelatory writing characterized by a variety of specific conventions. A common definition is: "An apocalypse is a genre of revelatory literature with a narrative framework in which a revelation is mediated by an otherworldly being to a human recipient, disclosing a transcendent reality which is both temporal, insofar as it envisages eschatological salvation, and spatial, insofar as it involves another, supernatural world" (Semeia 14 [1979]). A well-known discussion of ancient Jewish apocalypses is John J. Collins, The Apocalyptic Imagination: An Introduction to Jewish Apocalyptic Literature (3d Ed; Grand Rapids: Eerdmans, 2016). Notably, the Astronomical Book and Book of the Watchers are among the earliest ancient Jewish Apocalypses we have. Modern readers are most familiar with Apocalypses through the writings of the Jewish and Christian Bibles. The Book of Daniel in the Hebrew Bible (specifically Daniel 7-12) is an Apocalypse from the mid 2nd century BCE, and the Revelation of John at the end of the New Testament is another Apocalypse (from the middle to late 1st century CE).

One thing that binds the writings of 1 Enoch together is that each writing makes the figure of Enoch the human visionary who receives the revelation. It was common within ancient Jewish literary culture to select a famous or prestigious figure from Jewish lore to feature as the supposed visionary who received the revelation in revelatory literature. Other famous examples are Ezra (4 Ezra), Baruch (2 Baruch), Moses (Apocalypse of Moses; Testament of Moses), and so on. The idea was not simply authorizing or legitimating the contents of the writing, but also that these Jewish writers liked to develop or think about beloved characters from their ancestral lore. The Collins book mentioned above is a good resource for this issue. See also Eva Mroczek, The Literary Imagination in Jewish Antiquity (New York: Oxford University Press, 2016).

Enoch was a prized figure for revelatory texts in Jewish literary culture because he seems to have been associated with having access to divine beings in traditions about him. Genesis 5:21-24 preserves such a tradition, though it is important to note that most scholarship does not think the Genesis passage is some original "source" for all the later traditions, but more likely a compressed version of wider myths about Enoch, his elevation to the heavens, and walking with the gods. The Book of the Watchers would be a more expansive version of similar myths about Enoch. On this, see James Vanderkam's important book, Enoch and the Growth of an Apocalyptic Tradition (Washington, DC: Catholic Biblical Association, 1984) and, more recently, Seth Sanders, From Adapa to Enoch: Scribal Culture and Religious Vision in Judea and Babylon (Tubingen: Mohr Siebeck, 2017). Sanders corrects some problematic ideas that had become entrenched.

Of further note, the texts of 1 Enoch specify not only Enoch as a recipient of revelation, but also somehow a writer of the revelation or someone who initiated a trustworthy chain of transmission for the revelation to be written down. It is important to note that scholarship does not simply accept these claims at face value. We instead interrogate them as literary strategies for framing, authorizing, contextualizing, and developing these writings at a time period long after the mythical Enoch. In other words, no one thinks Enoch wrote any of these texts or that the texts preserve real revelations that were given to Enoch. On the literary strategies and conventions involved in writing these revelatory texts, see the books referenced above by Mroczek and Sanders. See also Annette Reed, Fallen Angels and the History of Judaism and Christianity: The Reception of Enochic Literature (New York: Cambridge University Press, 2005) and her new book, Demons, Angels, and Writing in Ancient Judaism (New York: Cambridge University Press, 2020).

The above should address or at least frame how to think about your questions. In short, no, there are no texts that "validate" the stories you would have read in 1 Enoch, because these writings are not transcripts of something that "really happened." They are literary imaginations about the politics of the heavens, what it would look like for a famous figure from Jewish lore to have a tour of the heavens (e.g., Book of the Watchers) and receive revelations from the heavens, and so on. these literary imaginations all fit alongside numerous other examples of ancient Jewish revelatory literature. This book was only "forgotten" by modern European Christians. Enochic writings are part of the Ethiopic Christian Bible to this day. But more than that (and Reed, Fallen Angels is excellent on this), ancient Jewish and, later, Christian writings continued to engage with and develop Enochic literature. The book of Jude in the New Testament even quotes the Book of the Watchers like it's an authoritative writing (Jude 14-15). The writings of 1 Enoch were "forgotten" to many later Christians because it was not included in their Bibles (that is a different discussion).

As for understanding what is going on in the texts (as opposed to asking about "what really happened," since we have no reason to think any of this "happened" or that Enoch even existed), it depends which writing from 1 Enoch you have in mind. Let me know which one and, when there is time, I will speak more to it.