It's not an external hard drive but a disk drive because my laptop doesn't have a disk slot
Ah, OK...
The external drive is not a hard drive, but an optical drive, which will read CDs and DVDs. Is that correct?
The optical drive is just a hardware device used to read and write to optical disks, and will
not appear on your desktop
until you insert a CD or DVD. Then, assuming the Finder Preferences allow it, you will see the disk appear on your desktop.
You do not need to format anything. A USB DVD drive will work, and you need to insert a disk in the drive so it can be used
![Big Grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Double click to open, or select it from the sidebar list (under Devices), and you will then be able to install your software.
You are running Yosemite (OS X 10.10.5)
From what I read, you may find that Logic Pro 9 is not going to perform very well, and you should probably upgrade to Logic Pro X, which requires the OS X version that you are using (OS X 10.10) or higher.