Excellent at writing characters, horrible at writing prose.

Hello all!

I have wanted to write a book for, well, forever. I am an avid D&D player, I love stories and worldbuilding, particularly crafting thematic characters with in-depth lore. Recently I challenged myself to take one of my characters and write a skeleton of a story around them; nothing too in depth, and certainly not overly ambitious. A tale of two families, two young people intertwined by fate and a historical betrayal working to end the cycle that their families are trapped in. Standard stuff, wrapped in themes I believe are digestible.

I have no idea how to start. That's the crux of the issue.

In my head, I can see the story, but that initial jumping point of the story doesn't come to me easily. I don't know if it's a bit of ADHD, the fact I lack creativity, or what. I know what I want to happen, but I don't want to get stuck in an infinite planning stage (something I avoid when drawing). Sometimes I feel like I have to wait to be hit with random inspiration, but I'd like to take a more active approach.

How do you decide what the first chapter should be? What grips readers? Should the first chapter include the inciting incident, or should I introduce my protagonist slowly?

I do occasionally write fanfiction, but obviously I have pre-determined worlds, themes, and events to work with - how do I begin my own!?

Any resources, groups, personal anecdotes or advice would be amazing - thank you!