Help on using Garner's Modern American Usage

Hello there. I am a non-native speaker. I am trying to write English Fiction. I recently purchased Garner's Modern American Usage (third edition). I am trying to understand how to write perefct english for publishing standards. I think my errors have to do with usage and style. I recently read an excellent book called The Sense of Structure: Writing from the Reader's Perspective by George Gopen. By structure is good. It's a good book for native speakers. My word choice is not.

So here I am asking for which topics in the table of contents should I read. I will try to read as much as I can but what concepts do I need to master. I liken this question as how to use Garner's Modern American usage. It is not friendly for non-native speakers. I feel intmidated.

Is there a web-page someone can direct me that explains how to use it for style and usage? Thank you very much!

I guess what I need is a introduction on it's proper use for my purpose (usage and style) and how to use it as a non-native speaker.