You probably don't want to log on as root. During installation, Mandrake should have prompted you to add a user, and that is who you want to log on. In any case, after logging on, the next command is normally:
If you did not add another user during installation, you will want to use "system > configuration > configure your computer" from the start menu to add yourself as a regular user now. You can also set it to log you (not root) on automatically and start the desktop when it boots. Running as root when not necessary is not a good idea.