Well, perhaps Harry Potter decides to build a school in Italy to spread the knowledge of magic in a new region. He might face challenges like getting approval from the Italian Ministry of Magic, if there is one in the fanfic. And he would need to find suitable teachers who are familiar with both the British and Italian magical traditions.
One possible plot could be that Harry, after all his adventures, realizes the importance of a new kind of magical education. He decides to build a school that focuses on teaching not only magic but also how to use it for good in the real world. He might gather his old friends and some new allies to help him find a location, design the curriculum, and recruit students from all over the wizarding world.
The school could be a place full of magic and innovation. Maybe it has special courses for female witches to master their unique magic powers. There could be gardens filled with magical plants that are used for potion - making and spell - casting practice.
In the 'Harry Potter builds a school fanfic', it could be that Harry wants to create a school for those who were left out of traditional magical education. He'd have to design the curriculum, which could include new spells and ways of magic. He might also face opposition from some in the Ministry of Magic who think his ideas are too radical. He'd need to find teachers who share his vision and are willing to break the mold.
Well, one possibility is that Harry Potter builds the school in a hidden location, away from the prying eyes of the Ministry of Magic. He might create a curriculum that focuses on both traditional magic and new, unique areas of study that he discovered during his adventures.
In the fanfiction, the first students could be a mix of young wizards and witches who have shown exceptional magical abilities but didn't fit into the traditional Italian magical schools. There might be a young wizard who has an affinity for ancient Roman magic but was not encouraged in his previous school. And a witch with a talent for transfiguration but was bullied in her old place. Harry Potter's new school in Italy could be their new home, where they can explore their magic freely.
Obviously, Harry Potter himself would be one of the main teachers. He could teach Defense Against the Dark Arts, given his vast experience in that area. Hermione would be a great fit for teaching Transfiguration or History of Magic, as she has a deep knowledge of both.
Hermione would be a great help. Her vast knowledge of magic and books could provide the necessary information for building the planet, like the right spells and magical theories.
Dumbledore might help in a spiritual or advisory way. Even though he's passed away, his wisdom could be passed on through memories or some magical means. Also, Hagrid could be a great help. He could assist in building areas suitable for magical creatures with his love and understanding of them.