When it comes to using SASS, there are multiple ways of setting up your workspace. Some people prefer to use command line tools (probably Linux people) and others prefer to use GUI applications. I'll cover both.
The 'Install SASS' page at
sass-lang.com covers this quite well. You can use SASS with Ruby (which can be installed from a Linux package manager or you can download the installer on Windows).
macOS comes with Ruby pre-installed.
Once you've installed Ruby, you need to install SASS (in some cases,
sudo may not be needed):
sudo gem install sass
Finally, you can check you've installed SASS with
Whilst there are a number of GUI Applications that you can use, I recommend Scout-App. It auto-builds and compresses your CSS files for you, on file save and supports macOS, Windows and Linux.