If you want to install SteamOS on a Windows PC, use ChimeraOS. To know how to install ChimeraOS on Windows, follow this detailed guide.

To install SteamOS, double click the icon labeled "Wipe Device & Install SteamOS." You'll get a pop up warning you that this process will permanently delete everything on your device.

Steam OS runs on Linux, which makes it complicated (but possible) to transfer files to a Windows-based PC or Mac. Fortunately, there are some easy workarounds; you can use portable media (USB-C ...

Check this comprehensive guide and learn how to install Windows on your Steam Deck via external and internal drives.

If not for expanding storage, Steam Deck owners should know how to reinstall Steam OS on the Steam Deck to avoid getting into a fix.