You can store items by using the Upsert<T> method. This method will suitably serialize your data structure and store it on the cluster. To store a document, just create a new Document object, and fill in the fields you need:

var doc = new Document<string>() {
  Id = "document_id",
  Content = "Hello World!"
};

You can store anything serializable in the Content field, not just strings.

After the document has been created, you can store it in the cluster by using the Upsert method:

bucket.Upsert(doc);

Upsert is a combination of insert and update and will either replace an existing item if it exists, or create it anew if it's not yet present.

To retrieve a document, use the bucket's GetDocument method. This contains status information and the contents of the document:

var result = bucket.GetDocument("document_id");
Console.WriteLine(result.Content); // Prints "Hello World!"