I wrote this for a person who did not understand the idea of "you are God".
In the Hindu traditions, saying "you are God" does not mean that you can choose to create anything, like the "manifestation trend" says. Rather, in Hinduism, reality, or Brahmaan is eternal and transforms through a cycle of creation and destruction (which can be a less concrete, such as how civilizations rise and fall too). So the role of God, or Eeshvara is one that's understood in different ways - the one that you mentioned and what's in the Abrahamic tradition is that God is separate from his creation. But since that is familiar to everyone, I'll explain the "you are God" part.
(Firstly, note that the term "Hindu" is an exonym for the residents of the region marked by the river Sindhu, or Indus, and the land was called "Hind". When we are talking about the religion, we are referring to the orthodox traditions which follow the Vedas written in Sanskrit. Veda translates to "Knowledge", and a more correct term for the religion would be Vaidika (Vedic) or Aastika (Soul Affirming) traditions of India).
Basically, the universe is understood to be comprised of at least two entities. The Purusha (Witness Consciousness, formless) and Prakriti (Nature, including bodies). The Sankhya philosophy of Sage Kapila outlined this concept the best, and every other philosophy builds upon it. Basically, Nature evolves itself for the sake of maturity of the Witness Consciousness through experiences, and this cycle repeats. Both Witness Consciousness and Nature are eternal, but Nature is changing, while the Witness Consciousness remains constant. The illusion is when the Witness Consciousness misidentifies itself with Nature and thinks it is a part of it.
The Yoga philosophy follows, and it has the same perspective. However, it posits that since the Nature is deceptive, one has to imagine a personal God, or Eeshvara and submit to it, and in this manner, you are able to detach yourself from Nature. Then Nyaaya, Vaisheshika and Poorva Meemaamsa philosophies follow with more or less the same ideas, with minor theological differences. But the later Vedanta philosophies are the ones that are ones that are of interest today. Of that, especially Advaita Vedanta, which is the Summary of the Sanskrit Books of Knowledge, which posits that you and God are not separate.
One of the keys to understanding this is by understanding the universe to be a dance - and in a dance, the dance and the dancer are one. Now, each of us can be understood to be a limb of the dancer, and while the arm can influence the fingers, it cannot influence the legs. This is similar to how we have a limited amount of free will, but we are subject to the world around us, which we have limited control over (and trying to control it never works out even though it seems like it should be possible). Other than as a dancer, you may model the universe as a multi-dimensional matrix which keeps changing its values in a certain pattern to play out a pattern, or story. The typical explanation in Hinduism is that the world is the Leela (play) of Krishna (who is a manifestation of Eeshvara), who is a prankster in his true nature. I guess this story should be from the Mahaa Bharata Ithihaasa (Epic) and the Srimad Bhagavada Maha Purana (Puranas contain the mythological lore, and while mythology is just stories, it functions like Aesop's Fables to convey the meaning).
Also along with that, you can also consider the idea that something a person creates is an extension of themselves. For example, when Tony Stark says "the suit and I are one". If you painstakingly create something, you are an artist, and the art is an extension of the artist. But an artist may also accidentally create something, in which case, it isn't really intentional (but one could say that's God's plan). Then a writer may create a story with several characters, all of which are made by their will, but only some of them would be their ideal characters, in which case, although the other characters were their will, only the chosen few would be their "Will" (not to like prove that the Jews are chosen, but to point at some moral behavioural rules, and predestination).
With the two above ideas - "universe as a dance", and "creations as extensions of oneself", I'd also say that there is no free will, or at least that it is limited (as much as a dancer lets their body loose somewhat). If free will does not exist at all ultimately, then it exists as an illusion. The outcome of this is that there is no requirement to submit to a God, because you are already in submission, and there is no state of existence outside of it.
Now coming to Vedanta philosophies. In Advaita (Non-Dualistic) Vedanta, as it's commonly misunderstood, this nature we see is not the same as Eeshvara. But rather, Eeshvara is said to be dreaming, and this world is a dream world with laws of physics for coexistence. It is Shudda Advaita (Pure Non-Dualism), where this Nature along with the Witness Consciousness is co-identified as Eeshvara. Dvaita (Dualism) is the philosophy that Abrahamic religions follow, but with a jealous God.
The others are Bheda-Abheda (Simultaneous Difference and Non-Difference, where the Non-Difference is more important), Dvaita-Advaita (Simultaneous Dualism and Non-Dualism, a form of Bheda-Abheda, where both the Difference and Non-Difference is equally important), Vishishta Advaita (Special or Nuanced Non-Dualism), Achintya Bheda-Abheda (Inconceivable Simultaneous Difference and Non-Difference) and Akshar Purushottam (Namesake (for worship) and Supreme (true) forms of God).