bench new-site one.example.com --no-mariadb-socket --mariadb-root-password changeit --install-app erpnext --admin-password changeit
I’ve copy pasted the command. If you read the command it has --install-app erpnext. If you are familiar with linux, bash and shell commands generally they have -h or --help for basic help.
The docker setup you chose was for production. Development setup is different.
docker ps command shows running containers
Do not use container if you haven’t used them before.
Read Container Basics. This is not the right forum to learn about containers.