Hermione would start by studying all the new things she could find. Ron would follow Harry's lead most of the time. Harry would use his instincts to figure out who to trust in this new future.
At first, they'd be really confused. But Hermione's intelligence would quickly kick in. She'd start analyzing how the magic works in this future and how it's different from what they know. Ron would probably complain a bit about how strange everything is, but he'd also be curious. Harry, having dealt with so many difficult situations, would be more focused on finding a way to get back if they need to, while also trying to understand the new social and magical order. They'd all have to learn new spells and ways of using magic that are common in the future.
Well, in the future they could encounter different versions of themselves or their descendants. Maybe they would find that Hogwarts has changed a great deal, with new spells being taught that were unimagined in their time. And they might have to face new dark forces that have emerged over the years, using both their old - school magic knowledge and learning new ways to combat the threats.
The Golden Trio's reactions would be diverse. Hermione would immediately start making mental notes about the new magic education system. She would be interested in how they teach Charms, Potions, and Transfiguration in the future. She might even try to get involved in some of the classes as an observer. Harry would be looking for the sense of community and camaraderie that he had at Hogwarts. If he doesn't find it in the future's system, he would be disappointed. Ron would be a bit overwhelmed by all the new gadgets and advanced magic used in the teaching process. He might long for the simpler days at Hogwarts, but at the same time, he would be curious about the new things he sees.
They might try to change certain events. For example, they could attempt to save Sirius earlier. Maybe they'd use their knowledge of future events to outwit Voldemort's plans more effectively in that time period.
Harry would likely be the brave and impulsive one. He might be the first to jump into action when they face challenges during their time - traveling adventures. His role could also be to use his natural leadership skills to guide the group.
One interesting concept could be how the Golden Trio - Harry, Hermione, and Ron - deal with changing the past and the potential consequences. For example, they might try to prevent certain tragedies from the original story, but in doing so, create new and unforeseen problems.
There's a fanfiction called 'First Year Redo'. In this story, the Golden Trio goes back to their first year and decides to focus on befriending some characters they didn't get to know well before. They also use their knowledge to prevent some small, but annoying things that happened in their first year from occurring again. It's a heartwarming story that shows how much they've grown since their first year at Hogwarts.
A lesser - known but great one is 'Time - Twisted Bonds'. In this story, the time travel element is used to create unexpected alliances and conflicts between the Golden Trio and the Black Sisters. It starts off with a bang as the characters are thrust into the different time periods, and the plot unfolds in a very thrilling way.
They'd probably start by observing how things work. The Titans are smart, so they'd quickly pick up on new technology and social norms. For example, if transportation is different, they'd figure out how to use it.
Another one is 'Time Travel Trials'. The plot here is that the Golden Trio travels back in time due to a dark magic experiment gone wrong. They land in a time when there is a civil war among the wizarding community. They must use their skills and knowledge to stop the war and also find a way to reverse the time - traveling spell. It's unique because it's not just about changing the past at Hogwarts but about a much larger scale event in the wizarding world.
One great time travel redo first year Golden Trio fanfiction is 'Back to the Beginning'. It beautifully reimagines their first year with the knowledge of what's to come. The characters are well - written and it adds new twists to the familiar Hogwarts events.