Connectivity Thunderbolt 2 to USB 3.1
I have a Late 2014 Mac Mini, 3.0ghz, 16mb RAM, 1 TB Fusion drive running OS 10.13.6 with 3 USB 3.0 ports and 2 Thunderbolt 2 ports. I asked several days ago if there was a way to connect from Thunderbolt 2 to USB3.1 (USB-3 connector) and one helpful gentleman suggested I get an Apple Thunderbolt 3 to Thunderbolt 2 which Apple says is bi-directional. I purchased the item on-line but I didn't do my homework. and I discovered I still needed a thunderbolt cable to connect to the Thunderbolt 2 port on my mini. Got a Thunderbolt Cable (2M) and was assured that it was what I needed. Connected Mini to Adapter with Thunderbolt (2M) cable and the adapter to the Portable SSD. Absolutely nothing happened. System showed nothing connected to the Thunderbolt 2 port. If i Connect the USB-A to USB-C (provided) the drive works fine abeit at the max USB3.0 output. My question is, are the mini display plugs identical to the Thunderbolt 2 plugs as Apple suggests? If so why make a distinction? I am becoming very frustrated. Any help out there? This whole thing is becoming expensive in both $s and time.
MBP, Mac OS X (10.4.9)