Gaming Linux From Scratch, which is based on the BLFS book, helps you install gaming support software, like Steam or Wine, on a new x86_64 LFS system.
Depending on what you want to install and its type, you may need Multilib Linux From Scratch (MLFS).
For Steam, it requires 32-bit software as the core of the client is 32-bit. With Wine, it depends on the build type. You can build for pure 64-bit, which is not recommended, and you can do pure 32-bit, which is also not recommended. However, there are two WoW64 modes, an older one and a newer one. WoW64 allows running both 64-bit and 32-bit Windows apps and games on x86_64. The new WoW64 mode doesn't need any Linux 32-bit libraries but needs the i686 MinGW-w64 toolchain, which also doesn't need any Linux 32-bit libraries. The older WoW64 mode on the other hand does require 32-bit libraries.
In cases where 32-bit libraries are needed, MLFS is a required prerequisuite for this book. MLFS with m32 extensions is the recommended choice to save disk usage and build times. mx32-bit at present time is not very useful for Steam or Wine and seems to have some motions of being phased out. MLFS allows you to build 32-bit apps and libraries, the libraries being the most important part to get Steam and pure 32-bit or older WoW64 for Wine to work.
Installing binary-only software on an LFS system is a contentious topic in the LFS community. However, a lot of people still want to play games and use Windows software on their new LFS system. GLFS shows how to go about it, allowing your LFS system to be a viable gaming platform. If you don't care about gaming, this book is probably not for you but it still offers instructions on how to install certain packages for 32-bit on 64-bit. It also offers instructions on how to install libglvnd, NVIDIA, CUDA, MinGW-w64, and Wine which you may still want to use.
You will be able to use Steam, play popular games using Vulkan and OpenGL, use the proprietary NVIDIA driver and CUDA if wanted, and run Windows software via Wine. For Windows software (through Steam and Wine), you will be able to convert the Direct3D instructions to Vulkan for optimal performance.
You can read the book here. The book is rolling release, like MLFS. The only online rendered version right now is System V, although you can download the edition of the book that has Systemd support.
Douglas Reno, Rahul Chandra, Thomas Trepl, Xi Ruoyao, and the GLFS contributors