Perhaps at a big gathering in the Great Hall. After all the chaos and battles, everyone is eager to hear his story. Harry stands up on the dais where the teachers usually sit and starts from the very beginning, about how he grew up not knowing he was a wizard, living with the Dursleys. He tells of the strange things that used to happen to him that he didn't understand at the time.
It could be that he starts telling his story while on a journey. Maybe he's on the Hogwarts Express with some new students, and they start asking him questions about his adventures. Harry then begins to share, bit by bit, his story. He might start with the Triwizard Tournament and how that was a turning point in his understanding of the real danger that Voldemort posed.
He might be very sad at first. Harry has always valued his friends, so being forgotten by them would be a huge blow.
Maybe a new exchange student from a far - off wizarding world where the concept of the Force exists comes to Hogwarts. This student notices Harry's strong magical abilities and decides to introduce him to the Force, starting his learning journey.
In some fanfiction concepts, he might change his soul through powerful magic spells. Maybe he discovers an ancient spell in a hidden book in the Room of Requirement that has the power to transform his very essence, his soul.
Fanfiction starting with Harry Potter could be due to several reasons. Maybe it's the rich magical world that offers endless possibilities for new stories. Or, it could be the strong fan base and the desire to explore different scenarios for the characters.
Well, first, you need a unique idea. Maybe think about an untold story from a minor character's perspective or a 'what if' scenario. That could be a great starting point!
He might go to Madam Pomfrey in the hospital wing. She has all kinds of potions and remedies to help with ailments, so she could easily give him something to soothe his stomach.
The phoenix might also be able to teach Harry in a way. Since it has its own kind of magic, it could show Harry things like how to control his magic better when it comes to difficult spells. It could demonstrate its own magic, like its ability to rise from ashes, and Harry could learn from that to be more resilient in his studies and face challenges in a new way.
Harry could also be angry. Despite understanding Dumbledore's generally good intentions, being tied to a bed against his will is a violation of his freedom. He might struggle against the restraints and demand to be released immediately, especially if he feels that Dumbledore is overstepping his boundaries.
In some fanfictions, Harry could rely on the help of his friends. Hermione, with her vast knowledge of magic and Hogwarts' rules, might find some overlooked evidence. Ron, with his loyalty and sometimes unexpected insights, could also play a part. Together, they could present a solid case for Harry's innocence.
He probably uses magic. For example, to water the plants, he can use a spell instead of a regular hose. And to fence the ranch, he might use a charm to create a magical barrier that can keep unwanted animals or people out.