digital/operation_nw/1 matches the site

public static DigitalObject Nightwatch_Digital_Publication()
{
    var nightwatchPublication = new DigitalObject()
        .WithContext()
        .WithId("https://linked.art/example/digital/operation_nw/1")
        .WithLabel("Operation Night Watch Publication")
        .WithClassifiedAs(Aat.WebPage);

    nightwatchPublication.IdentifiedBy = [new Name("Operation Night Watch")];
    nightwatchPublication.WithFileSize(220, MeasurementUnit.Kilobytes, "220 kb");
    nightwatchPublication.AccessPoint = [
        new DigitalObject().WithId("https://www.rijksmuseum.nl/en/stories/operation-night-watch")
    ];
    nightwatchPublication.Format = "text/html";
    nightwatchPublication.ConformsTo = [
        new InformationObject().WithId("http://w3.org/TR/html")
    ];

    var creation = new Creation()
    {
        TimeSpan = new LinkedArtTimeSpan
        {
            BeginOfTheBegin = new LinkedArtDate(2019, 7, 19),
            EndOfTheEnd = new LinkedArtDate(2019, 7, 21)
        },
        CarriedOutBy = [
            new Group()
                .WithId("https://linked.art/example/group/rijksmuseum")
                .WithLabel("Rijksmuseum")
    ]
    };
    nightwatchPublication.CreatedBy = creation;

    nightwatchPublication.DigitallyCarries = [
        new LinguisticObject()
            .WithId("https://linked.art/example/text/operation_nw_en")
            .WithLabel("Operation Night Watch in English")
    ];


    return nightwatchPublication;
}

• Dimensions and physical description Each helper builds a Dimension with its AAT type, value and unit, or a classification with its metatype: height, width, colour, shape, page count, component count, file size, duration in days.

var digitalObject = new DigitalObject
{
    Context = ["https://linked.art/ns/v1/linked-art.json"],
    Id = "https://linked.art/example/digital/operation_nw/1",
    Label = "Operation Night Watch Publication",
    Dimension =
    [
        new Dimension
        {
            Label = "220 kb",
            Value = 220,
            Unit = Aat.Kilobytes,
            ClassifiedAs = [Aat.FileSize],
        },
    ],
    ClassifiedAs = [Aat.WebPage],
    IdentifiedBy = [new Name("Operation Night Watch")],
    CreatedBy = new Creation
    {
        CarriedOutBy =
        [
            new Group
            {
                Id = "https://linked.art/example/group/rijksmuseum",
                Label = "Rijksmuseum",
            },
        ],
        TimeSpan = new LinkedArtTimeSpan
        {
            BeginOfTheBegin = new LinkedArtDate(2019, 7, 19),
            EndOfTheEnd = new LinkedArtDate(2019, 7, 21),
        },
    },
    AccessPoint =
    [
        new DigitalObject
        {
            Id = "https://www.rijksmuseum.nl/en/stories/operation-night-watch",
        },
    ],
    ConformsTo =
    [
        new InformationObject
        {
            Id = "http://w3.org/TR/html",
        },
    ],
    Format = "text/html",
    DigitallyCarries =
    [
        new LinguisticObject
        {
            Id = "https://linked.art/example/text/operation_nw_en",
            Label = "Operation Night Watch in English",
        },
    ],
};

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.