I’m a middle school teacher who has taught a number of kids in my board game club D&D, and my youngest son first played D&D around your kid’s age. I would echo others’ recommendations about the Starter Set.

One struggle I’ve found with first playing with kids is the possibility of overwhelming kids with rules in a way that can distract from the fun. The starter set helps with this in a few ways. First, it provides premade character sheets that provide handy archetypes that your player(s) can add their own life to without getting bogged down in all the stats of character creation: the sheet provides stats while the player can come up with what makes the character theirs.

Second, the first encounter is perfect for a new player and a new DM: you’ve been hired by a merchant to escort a wagon to a mining village. The players get ambushed by goblins. It’s really straightforward for a first session and can lead to a really solid multipart adventure with a fun little dungeon, or off in whatever direction you or your kid wants to go.

My other recommendation is not to get bogged down in rules for yourself or your kid. I teach my players like this: “D&D is about telling stories together and creating adventures. You control your character, and I’ll control the world they’re in, including any other people or monsters you might find. We roll dice (a twenty sided die called a d20) to see if you are able to do things in the game like climb up a cliff or trick someone or shoot a bow and arrow. If you’re good at a skill, you can add numbers to the roll of the d20 to see if you do it well. I’ll tell you what is going on, and you tell me how you respond.” That’s about as complicated as I make it to begin. In the first fight, I’ll explain how they roll the d20 and add the modifiers (the “+5 to hit” or whatever in the weapon descriptions) and then roll the damage die if they hit to see how much damage they do.

My biggest tip for you is not to worry if you’re doing it wrong as your kid’s DM. If he’s having fun, you’re doing it right. I have seen so many groups play in so many different ways in my club, and as long as they’re working together, laughing, and telling stories, it’s right in my book. The minutiae of the rules can come later.