This image was taken in Zorin 16 Core using Zorin Default DE:
/home/swarfendor437/Pictures/Optical Drive on Desktop after inserting CD.jpg and right-clicking to select "Open in Files":
Then Files shows the root folder of the CD (below the CD is the USB stick):
/home/swarfendor437/Pictures/Viewed in Files before opening to view files.jpg
Then I double clicked on the CD to see what is present:
/home/swarfendor437/Pictures/Files on CD.jpg
In this case some nvidia based files and an nvidia screensaver.
If I had selected 'Open' on right-click I would see the files as above.
Naming of drives is different in Linux and tend to be labeled 'sr0'.
From a directory tree perspective, if you open your Home folder and select 'Other locations' you will see 'Computer' - open this, then go to media, then your username (in my case swarfendor437) and in the right-pane you will see the CD root directory as shown in the picture below: