docker run -p 8080:8080 mltooling/ml-workspace:latestshould be enough to test the workspace (just access http://localhost:8080). The only requirement is a working docker installation. If it is not working for you, you might try a different port e.g.
docker run -p 8081:8080 mltooling/ml-workspace:latestor a restart of the docker daemon/macbook. Have you tried other docker containers? What are the logs you get?
conda create -n myenv python=3.6
source activate myenvy
conda install ipykernel
python -m ipykernel install --user --name myenv --display-name "Python (myenv)"
jupyter labextension install @oriolmirosa/jupyterlab_materialdarkerin the terminal will install the material darker extension. In Jupyterlab there is also an UI to search and install Jupyterlab extensions (Accessible from the left menu - the puzzel piece)