Best books or sites about syntax?

I've been a self-taught writer for years but have never had a proper grasp for syntax. I can stumble my way into a properly laid out sentence with internet searches and Grammarly, but I want to learn the rules. Have a point of reference. A cheat sheet perhaps.

Does anyone have a great book recommendation or online resource on syntax? For beginning level writers if possible. I'm not beginning level, but I'd like to start studying proper syntax from the ground up.

Thanks,

Bradford Combs