Larian Studio's Divinity: Original Sin 2 isn't just regarded as something of a masterpiece from its embedded story content alone. It's customizability was likely a major selling point. Here's how you can get started.
Obviously modding a game through internal or external tools isn't a walk in the park. Things like that take planning, understanding of the tools, and a heck of a lot of time. But Larian put a lot of effort into having these tools be accessible to the general public. Hence why they're selling it so hard on their YouTube channel.
Divinity: Original Sin 2 contains what's known as 'Game Master Mode' - a tool that turns the game into your own custom D&D-like campaign. Tabletop fanatics have been crafting their own stories and hosting local game nights for decades, and the Game Master Mode turns each of those tabletop experiences into their own co-op video game.
Ready in time for launch, Larian has their own 30 minute beginner tutorial up on YouTube to each wannabe game masters the ropes. But if you're looking to see how it all plays out once pieced together, look no further than their own 4-hour long campaign hosted by Matt Mercer himself - the voice of Resident Evil's Leon, countless Fire Emblem characters and the host of an obscene amount of Critical Role episodes.
So if you're a budding Game Master, D&D fan or just simply enjoy watching Critical Role to get an insight into the dangerously addictive D&D world, the Game Master mode in Divinity: Original Sin 2 could be a fantastic and relatively inexpensive way to experience it all first hand.