GraphQL Getting Started Code Fragment 6

GraphQL6.js

const Skill = new GraphQLObjectType({
  name: 'Skill',
  description: 'Represents skill',
  fields: () => ({
    _id: { type: GraphQLString },
    name: { type: GraphQLString }
  })
});

const SkillLevel = new GraphQLObjectType({
  name: 'SkillLevel',
  description: 'Describes how well user knows certain skill.',
  fields: () => ({
    _id: { type: GraphQLString },
    level: {
      type: GraphQLInt,
      description: 'Actual skill level, ranked from 1 to 3'
    },
    favorite: { type: GraphQLBoolean }
  })
});

Hi, thanks for your article about GraphQL, I am following it :)
question about this script, in your article you mentioned with above code we will be able to query skill and skillLevel in GraphiQL.
I think we need to add something in Query? just like helloQuery and Users. Please advise, thank you again