https://docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/
Note: I was getting this error "E: Unable to locate package mongodb-org" in order to resolve this issue i had to modify this line echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-4.2.list
mongo --version service mongod start