The baron’s carriages have been tucked away in the carriage house by the time you arrive. Like the rest of the town, the house is made of sturdy wood, but someone has constructed a beautiful carved wooden archway leading up to it (although as there is not any sort of fence or gate, the archway is kind of just standing there). Nyna disembarks from the wagon and approaches the door, before gesturing at Savil to actually knock on it.
The door is answered by a young woman, who briefly exchanges words with Nyna before inviting the pair of them into the house. A few minutes later, she emerges from the house, looking rather more composed than she had on your journey.
“His lordship and his daughter will speak to you over supper,” she says. “Do please ensure that you are on your best behavior.”
She blinks. “You will want to clean yourselves, of course. You will also need to address him with appropriate courtesy, and refrain from any impolite or ill-mannered behavior.”
She seems to believe that this is a useful and adequate explanation, despite the fact that it contains almost no useful information.
“In addition, he has favored his daughter highly — she resides in this town, and in practice it is largely under her authority. Under no circumstances should you speak ill of her.”
(How might he learn what this actually means? [realistically, his good diplomacy would likely tie in to avoiding social faux pas, but preferred to actually know what he’s doing it])
The easiest way would be to have one of the casters cast Prestidigitation on you and your clothing, but in theory saunas are also a thing (and used for bathing purposes, rather than being a random fun summer camp activity or whatever). (It would definitely not be possible to hand-wash laundry non-magically before dinner, but Nyna owns several outfits! However, if you do not own multiple outfits, this may not help you very much,)
Yes, it’s common knowledge — if you’re speaking of him in the second person, you call him “my lord”, and if you’re speaking about him in the third person, you would say “His Lordship”. Alternative third-person constructions are acceptable if it would otherwise be unclear who you’re talking about (we’ve seen them used even by characters like Nyna), and there are various alternative polite constructions that could also be considered acceptable.
There are a large number of complicated etiquette rules about things like which silverware to use/et cetera, but if your character just mirrors what the other characters are doing you’re unlikely to majorly fuck up. (Also, when your character is given their seat, it would be considered very rude to try to switch, unless you’ve been seated further from the Most Important Person than someone you unambiguously outrank, in which case rudeness is more complicated (since it would be regarded as very rude to have seated you like that in the first place, but appropriately drawing attention to it could be complicated to navigate).)
It could also be perceived as a sign that you aren’t rich/high status if you don’t have a hat/other headwear, but it would be very rude to wear your hat indoors — the rich/high status thing to do is to remove your hat when you actually enter the building. But not having a hat isn’t rude , it would just be taken as a sign that your character is not as rich as the baron (which is true). (This is a stricter guideline for men than for women — for women it’s somewhat regional, although people with long hair and young children very commonly tie their hair back in some way, since babies really like to pull on people’s hair. In Granite Hill hats for women are non-default.)