you need to mount (think of it as reading) any external drives / other partitions other than ext2 / 3 which linux runs on.
do a "man mount" to read if you have time
if you don't have time, read the following to see if it helps
you should only have to do
mount /dev/cdrom /mnt/cdrom
/mnt is a directory where you normally mount things to, if /mnt/cdrom doesnt exit, you need to create it first, simply "mkdir /mnt/cdrom"
The latest distro will mount cd rom automatically, all you need to do is to click an icon somewhere
for a file on the disk, if it is in linux partition, all you need is the right software to access the file, for a plain .txt file, you can use command "cat/more/less" to view it and "vi/emacs" depending on your taste.
for a file that's on a different partition such if you have a windows partition like FAT or NTFS, you need to mount them with the right driver, most linux distro comes with FAT driver, you might need to download NTFS driver separately
mount -t fat /dev/hda1 (<-- whichever disk it is on) /mnt/windows (<-- create it if non-existing)
as root, do
modprobe ntfs (<-- be sure you have the ntfs driver installed correctly)
mount -t ntfs /dev/hda1 (<-- whichever disk it is on) /mnt/windows
ntfs will be mounted as read-only, among everything i read they all say it's not recommended to write to it. I know there are things you can do to write to ntfs, never tried.
hope this helps! I am a linux newbie too. Feel great to switch to the linux site after playing with the dump windows