Model Solar System Help

Hello! I’ve read the rules and believe this post to be allowed, but if it is not please forgive me!

I am not scientifically savvy but I do love space and have been writing a story involving space travels. I want to build a solar system with planets that “makes sense” or, in other words, a model that is physically possible. Specifically, 3 planets within the habitable zone of its star.

I’m not sure where to begin and would love to learn on my own, but I have no idea where to start. If there’s anyone that thinks this could be a cool project (or could steer me to good resources) I would be greatly appreciated.

Thanks again!