GLFS stands as a format in between LFS and BLFS so this part is crucial to understanding what you need to read and/or follow in order to get out of the system that you desire. For starters, LFS is meant to be followed in a linear manner, whereas BLFS handles things by putting related packages in the sections they are best described as categorically. For example, printer software being in a printer section, although most packages can be discarded by the user.
Not every chapter will be necessary depending on what you want. Some packages may also not be necessary.
By default, every user should read the multilib chapter. If that chapter is skipped, you might get a headache later on.
The following chapter is Shared Dependencies. Every user who wants Steam and/or Wine will want to read this chapter as both projects use the packages. Most of this chapter is necessary. However, it is recommended to check the dependency lists of Steam and Wine to see what exactly you need from a given section. If you are in doubt, (re)install all of the listed packages in that chapter. If you don't use them in this book, it still may be useful for some packages in BLFS.
The next chapter is Steam, which covers all the packages, patches, configuration, and setup necessary to get Steam working and capable of the playing the following: Linux games, Windows games via Proton, and games using OpenGL, Vulkan, and Direct3D.
The following chapter that most users will need is Wine. Users should follow every step in this chapter if they want to install WoW64 Wine, but more information is covered in that chapter. The Wine chapter at the moment does not consider retrofitting and will handle it in a similar manner to Arch: build the MinGW-w64 toolchain, install the audio and video components, then finally Wine itself.
The last chapter covers quality of life improvements and packages. This chapter is not required but recommended.
We hope you enjoy using GLFS and that it provides you most of your gaming needs!