// Write
Schema schema = Schema.Lookup(new Guid("4E5B6F62-B8B3-4A2F-9B06-DDD953D4D4BC"));
if (schema == null)
{
    schema = CreateSchema();
}
var entity = new Entity(schema);
entity.Set("SomeValue", 888);
element.SetEntity(entity);

// read
var schema2 =
    Schema.Lookup(new Guid("4E5B6F62-B8B3-4A2F-9B06-DDD953D4D4BC"));
if (schema2 != null)
{
    var entity2 = element.GetEntity(schema2);
    var someValue =
        entity2.Get<int>("SomeValue");
    TaskDialog.Show("Entity value", someValue.ToString());
}


private Schema CreateSchema()
{
    SchemaBuilder schemaBuilder =
        new SchemaBuilder(new Guid("4E5B6F62-B8B3-4A2F-9B06-DDD953D4D4BC"));
    schemaBuilder.SetSchemaName("SimpleIntSchema");
    schemaBuilder.AddSimpleField("SomeValue", typeof(int));

    return schemaBuilder.Finish();
}