Welcome.
I'll leave the fundamentals for another user to fill you in on and just give you my 2 cents about the whole thing. When I was younger I thought the same thing as you're thinking now, that it would 'pierce the veil of reality' and produce all these magical things. Got all hyped up by going over all I could of McKenna's work (shout out to Lorezno's Psychedelic Salon podcast!) and so on. And it is visually astounding no doubt, it
feels both revelationary and nostalgic like you've been there before many times, a very shockingly different experience to our ordinary waking state.
But, for me personally, in the end it only posed more questions than it answered, and some 10 years later I now regard the experiences as both life changing and no more important than a finger on my hand. Visions are just that, visions. They don't tell you much about the screen it's projected on, or who is watching.
Go watch the film though. It's great. Just don't buy all the merchandise and wear the t-shirt every day afterwards, OK?