text/catalog_24477/1 matches the site

public static LinguisticObject Auction_Catalog()
{
    var catalog = new LinguisticObject()
        .WithContext()
        .WithId("https://linked.art/example/text/catalog_24477/1")
        .WithLabel("Auction Catalog")
        .WithClassifiedAs(Aat.AuctionCatalog, Aat.TypeOfWork);

    catalog.IdentifiedBy = [new Name("Impressionist & Modern Evening Sale Catalog").AsPrimaryName()];

    catalog.About = [
        new Activity()
            .WithId("https://linked.art/example/event/christies_24477")
            .WithLabel("Impressionist Sale")
    ];

    return catalog;
}

• Metatype classification The second argument classifies the first, not the object: WithClassifiedAs(Aat.Description, Aat.Statement) says this is a Description, and Description is a kind of Statement. The Plain C# form shows the nesting.
• Role shortcuts AsPrimaryName, AsAccessionNumber and AsSystemAssignedNumber each add a single classification, with the AAT terms Primary Name, Accession Number and System Number.

var linguisticObject = new LinguisticObject
{
    Context = ["https://linked.art/ns/v1/linked-art.json"],
    Id = "https://linked.art/example/text/catalog_24477/1",
    Label = "Auction Catalog",
    ClassifiedAs =
    [
        new Type("http://vocab.getty.edu/aat/300026068", "Auction Catalog")
        {
            ClassifiedAs = [Aat.TypeOfWork],
        },
    ],
    IdentifiedBy =
    [
        new Name("Impressionist & Modern Evening Sale Catalog")
        {
            ClassifiedAs = [Aat.PrimaryName],
        },
    ],
    About =
    [
        new Activity
        {
            Id = "https://linked.art/example/event/christies_24477",
            Label = "Impressionist Sale",
        },
    ],
};

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.