You can either download the single file import via the latest Github release or alternatively fetch Keyfram through its NPM package:
npm install --save kf-sass
Next simply import kf.scss as an import in your main SCSS/Sass file:
@import 'relative/path-to/kf.scss';
Alternative: Live playground
If you just want to play around before installing - you can use the live playground instead which preloads Keyfram in a live Sass.js environment.