The Docker Desktop extension framework is currently in Beta and therefore, these instructions will change as this matures into the Stable release cycle.
In the future, you'll be able to execute the commands docker extension by default but, at the moment this requires manual configuration.
Download the docker-extension binary from https://github.com/docker/extensions-sdk/releases/tag/v0.2.4 and then configure as a plugin using the steps outlined here - https://docs.docker.com/desktop/extensions-sdk/#prerequisites (essentially, moving the docker-extension file to ~/.docker/cli-plugins).
Once complete, from this repository (if you want to build locally) you should be able to use the following commands -
docker extension ls
# docker should be up and running.
make build-extension
# or alternatively, if you haven't got make run: docker build --tag=beginneracademy/docker-extension:latest .
docker extension install beginneracademy/docker-extension:latest
docker extension uninstall beginneracademy/docker-extension:latest