In addition to the existing answers, a clean OS install of Windows 10 is somewhere around 10 GB, depending on what exactly is installed. I did even manage to get it down to 7 GB once. This will grow over time as patches are applied, browsers build up huge caches on disks, and logs grow. When space gets scarce, Windows will do some cleanup on its own, and let the user know to run Disk Cleanup (right click on the drive->Properties).
If you run Disk Cleanup, and also click "Clean up system files", then check all the boxes, your Windows folder will become considerably smaller than 32 GB.
Additionally, any program you install stores a footprint directly in the Windows Directory, in folders like