The Guide shows you Step-by-Step How to Install MongoDB NoSQL Database for Fedora 18 GNOME3 Desktop.
Finally, the post’s Content is Expressly Reduced to Give Focus to the Essentials Instructions and Commands.

Open a Terminal Window
(Press “Enter” to Execute Commands)Ctrl+Alt+T.
SetUp Yum Repo for Latest MongoDB Installation:
MongoDB Yum Repo SetupInstalling the MongoDB Database for Fedora 18
sudo yum install mongo-10gen mongo-10gen-server
Starting the MongoDB Server
service mongod start
To Enable Start at Boot:
chkconfig mongod on
To Stop MongoDB Server:
service mongod stop
To Restart MongoDB Server:
service mongod restart
MongoDB Database Getting-Started Guide.