assuming docker is installed and running in the machine and the Dockerfile is in the working directory.
use the command sudo docker build -t <image name:version> . to build the image.
The previously image created uses as base image the "official" fastapi image hence it is possible to override sensible configuration variables (e.g. Gunicorn configuration variables) in the docker run command. For more information refer to this link.
to run the image use the command sudo docker run -d --name <container name> -p <host port>:<container port> <image name:version>.
Notice that by default the container is listening on port 80 to override this value use -e PORT=<container port>.