activity/exhb/1 matches the site

public static Activity Manet_and_Modern_Beauty_AIC()
{
    var activity = new Activity()
        .WithContext()
        .WithId("https://linked.art/example/activity/exhb/1")
        .WithLabel("Manet and Modern Beauty (AIC)")
        .WithClassifiedAs(Aat.Term("300054766", "Exhibiting"));

    activity.IdentifiedBy = [new Name("Manet and Modern Beauty").AsPrimaryName()];

    activity.TimeSpan = new LinkedArtTimeSpan()
    {
        BeginOfTheBegin = new LinkedArtDate(2019, 5, 26),
        EndOfTheEnd = new LinkedArtDate(2019, 9, 8).EndOfDay()
    };

    activity.TookPlaceAt = [
        Tgn.Place("7013596", "Chicago")
            .WithClassifiedAs(Aat.City)
    ];

    activity.CarriedOutBy = [
        Ulan.Group("500304669", "Art Institute")
            .WithClassifiedAs(Aat.Museum)
    ];

    activity.UsedSpecificObject = [
        new Set()
            .WithId("https://linked.art/example/set/exhset")
            .WithLabel("Exhibition objects")
    ];
    activity.InfluencedBy = [
        new PropositionalObject()
            .WithId("https://linked.art/example/concept/exhidea")
            .WithLabel("Idea for Manet and Modern Beauty")
    ];

    activity.PartOf = [
        new Activity()
            .WithId("https://linked.art/example/event/exhab")
            .WithLabel("Manet and Modern Beauty")
    ];

    return activity;
}

• Role shortcuts AsPrimaryName, AsAccessionNumber and AsSystemAssignedNumber each add a single classification, with the AAT terms Primary Name, Accession Number and System Number.
• Terms outside the registry The vocabulary registry holds only the terms linked.art itself publishes, so a dataset's own concepts, places and people are written with Aat.Term, Tgn.Place and Ulan.Person, giving the id and the label.

var activity = new Activity
{
    Context = ["https://linked.art/ns/v1/linked-art.json"],
    Id = "https://linked.art/example/activity/exhb/1",
    Label = "Manet and Modern Beauty (AIC)",
    ClassifiedAs = [Aat.Term("300054766", "Exhibiting")],
    CarriedOutBy =
    [
        new Group
        {
            Id = "http://vocab.getty.edu/ulan/500304669",
            Label = "Art Institute",
            ClassifiedAs = [Aat.Museum],
        },
    ],
    IdentifiedBy =
    [
        new Name("Manet and Modern Beauty")
        {
            ClassifiedAs = [Aat.PrimaryName],
        },
    ],
    TimeSpan = new LinkedArtTimeSpan
    {
        BeginOfTheBegin = new LinkedArtDate(2019, 5, 26),
        EndOfTheEnd = new LinkedArtDate(2019, 9, 8, 23, 59, 59),
    },
    TookPlaceAt =
    [
        new Place
        {
            Id = "http://vocab.getty.edu/tgn/7013596",
            Label = "Chicago",
            ClassifiedAs = [Aat.City],
        },
    ],
    UsedSpecificObject =
    [
        new Set
        {
            Id = "https://linked.art/example/set/exhset",
            Label = "Exhibition objects",
        },
    ],
    PartOf =
    [
        new Activity
        {
            Id = "https://linked.art/example/event/exhab",
            Label = "Manet and Modern Beauty",
        },
    ],
    InfluencedBy =
    [
        new PropositionalObject
        {
            Id = "https://linked.art/example/concept/exhidea",
            Label = "Idea for Manet and Modern Beauty",
        },
    ],
};

Generated from the object the example builds: every property that is set, as object initialisers, with the vocabulary constants where a term is in the registry. The fluent helpers are a convenience, not a requirement; this form and the one as written produce the same JSON.