Load disc on to your computer. Launch iTunes. From the menu across the top of the page go to 'File', then 'Add to library'. Navigate to the .mp3 music files that are on the disc you inserted earlier, highlight all of them and click on 'Choose'.
(The above is on a Mac but I'm presuming it'll be the same on a PC).
It is not a music disc but a 60 track MP3 cd of steam train sounds & when I put it into my computer all it does is ask me to open folder to view files when I do that a file opens showing other stuff on my files but not the files on the new disk.
You could try this?
When the box opens and asks you to open the folder, just close that box and open Windows Explorer instead. Look down the list of folders & directories until you find the CD drive, Click the plus sign on the left to open the drive. It should show you the MP3 CD as a folder and if you open that it should show a list of files in the right side panel.
Right click a file and select PLAY.
If that works then I'm sure you can sort out how to get them into iTunes.