Open terminal.
if you have never done it and you are on MacOS run xcode-select --install (takes quite some time).
clone the repository and install all the packages by running npm install in the root folder.
You must have node installed, and if not run:
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.1/install.sh | bash
in the terminal to install NVM (manages the versions of Node)
after that run source ~/.zshrc to reload the terminal environment.
If everything went well you should see a number output by the command nvm -v.
Then you can install node by running nvm install node (for the latest version).
Once done you can run npm install and npm start to launch the local environment. You can also run npm test to run some tests.