How did I install MongoDB to Debian 9?

wget -qO - https://www.mongodb.org/static/pgp/server-4.2.asc | sudo apt-key add -
echo "deb http://repo.mongodb.org/apt/debian stretch/mongodb-org/4.2 main" >> 5.9.188.84/etc/apt/sources.list
apt-get install -y mongodb-org

docs.mongodb.com/manual/tutorial/install-mongodb-on-debian

How did I make MongoDB to run via SysVinit on Debian 9?