What is an mp3 disk?

Well, the simple answer is that it's a disk with sound recordings in mp3 format on it!
You'd probably already figured that out...
Ok, so what can I do with an mp3 disk?
Lots of things!
The simplest way to use one of my mp3 disks is to put it in your Desktop PC, Laptop, All-in-one, Mac or whatever sort of computer you have (assuming it has a CD/DVD drive, of course), load up the included Index file which is just a web page and off you go. Using that, you'll find your way to the recordings and notes; it's just like using a web site.
Of course, you don't have to do that, you can just use Windows Explorer or Finder to locate the files you want to hear and play them that way in Media Player, iTunes or similar but you'll probably want to transfer them to something portable like an mp3 player or mobile phone. You can freely copy them off the supplied disk just as you would with your music files and, if you are using a smart phone or tablet you could also copy the included Adobe Reader files so that you can read the notes while you listen.
The disk will also allow you to play the recordings in most DVD players and many CD player.
Perhaps what you really wanted were audio CDs?
No problem. Buy yourself some recordable CDs and using suitable CD burning software (Windows users can do this from Media Player) you can use the files to make audio CDs.
So, what can't I do with an mp3 disk?
As you'll have read, you can copy all these recordings and other files quite freely; there's no copy protection or anything of that sort and indeed, I'd encourage you to make a backup copy just in case anything happens to the original but, and I'm going to have to trust you on this one; however tempting it may seem, please don't make copies to give to all your friends!
The content on these disks is copyright and while I'm giving you permission to copy them for your own use, just remember that the idea behind selling them is to help me pay for web site hosting. I'm not running a business here, it's really just a hobby so please just make copies for your own use.
Of course, you can tell your friends how good they are and let them have a listen then, perhaps they'll buy one too; that would be really good!