C# not finding package with GraphQL

Question

Following a tutorial at the moment to do with C# Azure functions and GraphQL. Having a little trouble with the Schema for the GraphQL Types.

Here is my Model User class:

public class User : Base
{

    private User()
    { 
    }

    public User(string name, string email, bool adminUser, DateTime birthday, string dietaryRequirements, Squad squad)
    {
        Name = name;
        Email = email;
        AdminUser = adminUser;
        Birthday = birthday;
        DietaryRequirements = dietaryRequirements;
        InformationRequired = true;
        Squad = squad;
    }

    public string Name { get; set; }
    public string Email { get; set; }
    public bool AdminUser { get; set; } = false;
    public DateTime Birthday { get; set; }
    public string DietaryRequirements { get; set; }
    public bool InformationRequired { get; set; }

    public Squad Squad { get; set; }

}

And the corresponding Schema in GraphQL:

public class Type
{
    private ISchema _Schema { get; set; }

    public Type()
    {
        this._Schema = Schema.For(@"
            type User {
                Id: GUID
                Name: string
                Email: string
                AdminUser: bool
                Birthday: Date
                DietaryRequirements: List<string>
                InformationRequired: boolean
                Squad: squad
            }

            input User {
                Id: GUID
                Name: string
                Email: string
                AdminUser: bool
                Birthday: Date
                DietaryRequirements: List<string>
                InformationRequired: boolean
                Squad: squad
            }
            
            type Mutation {
                createUser(input: User) : User
                getUsers() : User
                getUserById(id: Id) : User
                updateUser(input: User) : User
                deleteUser(id: Id) : string
            }
            
            type Query {
                users: [User]
                user(id: Id) : User
            }
  ", _ =>
        {
            _.Types.Include<Query>();
            _.Types.Include<Mutation>();
        });
    }
}

}

I am following this tutorial: https://softchris.github.io/pages/dotnet-graphql-serverless.html#adding-a-graphql-schema under the "Adding a GraphQL schema section".

The issue I am having is with the last few lines of the Type class where I have:

_.Types.Include<Query>
_.Types.Include<Mutation>();

IntelliSense is throwing up an error here as it does not find the namespace required for this. For the Query it recommends adding using static Microsoft.EntityFrameworkCore.DbLoggerCategory; but the original author does not use this package so I assume it is wrong. Similarly, for Mutation, it has the same error but does not recommend any packages to import.

Can anyone see what I am doing wrong here or any errors I am failing to pick up one?