The best way to find out where you CDrom drive is is to try
Sometimes this is in the /usr/sbin/ directory and you need to type the entire location. This will list everything in /proc/partitions. Then you will know exactly what command to issue to mount the CDrom. Make sure the directory you are trying to mount to exists, i.e., don't try to mount to /mnt/hdc if /mnt/hdc does not exist.
Typically mounting/unmounting can only be done by root, unless a certain drive is specified as otherwise in the /etc/fstab file. If you don't know anything about fstab, read this: http://www.tuxfiles.org/linuxhelp/fstab.html
In addition, there is a program called "sudo" that allows regular users (only those specified in the sudo configuration) to run root commands without having full root access, like knowing the root password. When sudo is configured, you just have to prepend "sudo" to the command you need to run as root. Take a look at the home page for sudo: http://www.courtesan.com/sudo/
Finally, newer versions of KDE and Gnome have an automount daemon that runs in the background. If this is running then KDE/Gnome should ask you what you want to do with your CDrom once a new CD in inserted. This is really the easiest way to use a CD, since you don't have to have any root permissions to do it. You can find out if automount is running by typing
You don't have to be root to do this either. Just look for /usr/bin/automount (or something similar) on the right side of the information it gives you.
Good luck on using/learning Linux. If you have any questions feel free to email them to me if you can't otherwise find the answer (my email is in my signature).