PASSPORT: MODEL WDBLUZ5000asl - 05

Hi,

I have PASSPORT: MODEL WDBLUZ5000asl - 05 and Mac OS Mojave 10.14.5

When I attach it to my mac, I can unlock it and a western digital icon shows up to click on and access my previous backup; however, I am unable to find where I initiate the back-up.

Could anybody help me with this?