ITVMO.gov is built using Federalist and USWDS, which runs the static stie generator Jekyll. The local environment can be set up using just Jekyll, no need for docker even though it's included in Federalist.
Always cut a new feature branch from main when developing, pushing up changes to your feature branch creates a Federalist link that can be shared internally with clients. Once a feature branch is merged with main, all changes from that branch will be pushed to production.
Jekyll is a static site generator built using Ruby. This project uses a specific version outlined in .ruby-version at the project root, and in the Gemfile. On windows you must have ruby installed manually, MacOS it already comes pre-installed. On Mac, the .ruby-version file only works with rbenv, install that and then from the project root run rbenv local which will add the corresponding version to your project. You don't need this for Windows, use RVM instead which can switch between versions on Windows.
Install bundler on your machine. This is a package manager for all your ruby gems and relies on the Gemfile to make your project work and fires up the local environment.
There are many guides out there for installing Node and it's package manager NPM. Once it's on your system, run npm install from the root of your project. This installs the dependencies needed for USWDS to run as intended in the project. You don't need to keep Node or NPM running in the background or do anything with the package.json file.
bundle install from the project root to pull down all of the gems that Jekyll needs to get started.bundle exec jekyll serve --watch which will start the development server. Always run with the --watch flag as this re-builds on changes and makes your files production ready._site directory, this gets built out every time a change is made. _includes and _layouts has files related to the overall look/feel of the site, _resources contains everything on the resources pages, and _pages contains the markup for all static pages on the site. All files within Jekyll utilize Liquid for the templating language. Follow the front matter patterns at the top of .md files, and all style changes can take place in assets. Using SCSS? Add or edit files inside the _sass directory and add their import reference in the css/main.scss file.