I’m excited about this post! I just got my first Alexa skill published. You can view and add it here: https://skills-store.amazon.com/deeplink/dp/B07K87JRK8.
I’m also providing the full source code to the lambda function for the skill in my github repository. Just zip it up and upload it to lambda. I’ve kept the code as simple as possible so you can follow along and build your own skill. The skill will take the input of “Can you give me a rating for Mario Maker” and will query the Game Query API for a rating then play it back. The API has a lot more features, feel free to build upon it.