Installation and setup is identical for Mac, Windows, and Linux. The only requirement is NodeJS which is likely available on your system, but if not, install NVM https://github.com/nvm-sh/nvm.
Cloud functions in either Node 6 or 8, so it is recommended that you setup your local env with. For example, with NVM
nvm install 8 nvm use 8
Setup Cloud Functions
npm install firebase-tools -g firebase login firebase init functions cd functions