To use Docker, you'll need either Docker Desktop or Docker Toolbox installed and setup based on your system.
You'll also need to prepare a local version of the project with a copied base ROM (see steps 2 and 3 of the Linux instructions).
From inside your local project, run the following command:
docker build . -t oot
To start the container, you can mount your local filesystem into the Docker container and run an interactive bash session.
docker run -it --rm --mount type=bind,source="$(pwd)",destination=/oot oot /bin/bash
Once inside the container, you can follow steps 4 and 5 of the Linux instructions to setup and build the ROM, or run any other command you need.