The links to the documentation for the extension need to point to the wiki (https://github.com/YoYoGames/GMEXT-Steamworks/wiki ). There are two instances of this, one in the section: "Set Up GameMaker" and one in the section "Updating your project to Steam".
The screenshot at the bottom of the guide is also outdated and should be replaced.
The guide should also mention the existence of this repository, possibly next to link to the extension on Marketplace.
The Steamworks SDK: Setting Up Your Game needs updating. (link here :https://help.yoyogames.com/hc/en-us/articles/216754138-Steamworks-SDK-Setting-Up-Your-Games )
Steps to reproduce