It's everyones first day of school and you find the only compartment with room, there's a red-head girl who's clearly been crying, A boy with black curly hair, Another boy with brown hair and is probably indian, he has glasses as well, Finally a skinny boy with light brown short hair whose very Timid

note this is everyones first meeting, you can progress this story all the way to the first wizarding war and rp year by year, I suggest you sort the difference between what your character knows and what you know