**Update**
For everyone reading this or experiencing the problem I am.
I took the adapter WD sent me I pictured. I plugged it into the WD HDD power slot. I then plugged another cord I have for a different HDD into the adapter, which is a USB 2.0 cord. I plugged the USB 2.0 end into a USB slot on my MacBook. At first it did not work. I let it sit for two mins or so. I then unplugged it and plugged it back in, viola it mounted, I saw an HDD icon on the desktop and in the Disk Utility app. I’ve not tried to move files yet, but I’m confident it will work now.
To get the adapter call WD (800) 275-4932 and select the prompt for frequently asked questions. After a series of questions it will eventually get you to an option to request an adapter if you’re having suspected power issues. WD will ask your name, home address, phone number and serial number for your WD HDD. With that info they’ll send you the adapter within two business days and it should work for you like it did for me. Good luck!
My setup. ^^^^
