Hello '''John Lang'''! If your laptop came with a caddy, then all you will need to do is slide a 2.5” HDD or SSD into it and slide the caddy back into the laptop. You should not need any extra cables or connectors. If you wanted to replace the caddy with an actual CD or DVD drive, you will most likely need to get a specific drive for use with your laptop otherwise the drive may not fit properly or not look correct compared to the rest of your computer. You would also need to install extra software and drivers for the CD or DVD drive to work properly. On top of that, CDs and DVDs are becoming increasingly less common and hold much less data than a traditional hard drive or SSD. My recommendation would be to install a spacious HDD drive to store documents and data that you do not want cluttering up your laptop’s main drive. You will be able to use an HDD or SSD just like an external drive that is connected to your computer after it has been formatted correctly. If you need faster data transfer speeds, a SSD will be a better option as it offers much faster performance compared to a HDD. However, SSDs are usually offered in much less capacity than a traditional HDD, and they are also much more expensive than a HDD. I hope this has answered your question and fixed any of your problems.