Chris Simpkins. "How to Manually Install, Update and Uninstall Fonts on Linux". Source Words, 12 March 2018.
This will install the fonts for the logged in user and not globally.
Download your fonts. In the example below, they're the TrueType font files for FiraCode.
$ mkdir .local/share/fonts
$ mkdir -p .local/share/fonts/truetype/firacode
$ cp Fira*.ttf .local/share/fonts/truetype/firacode
$ fc-cache -f -v
Verify it worked:
$ fc-list | grep "Fira"
Installs the fonts for the logged on user.
Download your fonts.
Highlight the font files, right-click, and select "Install".
(this will install them under C:\Users[yourusername]\AppData\local\Microsoft\Windows\Fonts).
Voila!