To be blunt, you advertised it instead of organizing it

Very few people are going to show up to a game night where they don't know anyone. Especially if they don't have a vibe check from hearing about it from someone they know directly

And if there's only one person there when they show up, most people are going to feel very awkward. It's likely they'd peek through the window and bail out

You need people to buy in. You need at least a core group that will be there before the start time so people will see a game night going on if they do show up, and to spread word that its a good time. It'll grow organically from there if everyone has fun, and that's the point where you can advertise if you want to keep growing

How you find that group I can't help with, but it can't just be like an RSVP on Facebook or something. You need to communicate with people directly what you're trying to do and organize with them