For the first command, it seems you might need to set the working directory inside your container. If you are following the guide it has you run

docker run -v $(pwd):/projects \
             -w /projects \
             meltano/meltano init yourprojectname

note the

-w

to set the working directory try running:

docker run -v $(pwd):/projects \
             -w /projects \
             meltano/meltano add orchestrator airflow