That sounds correct, so far, except why did you switch it off at the rear?
Do you own the VU+ Duo 2?
If so let's try again:
Format your USB stick to FAT 32, on your PC.
Download, and uncompress, the latest VU~+ Duo 2 Blackhole image:
Once unzipped load the vuplus folder onto your USB stick.
Go to your receiver and switch it off, at the rear.
Pull down the front flap, on the right hand side, and insert the USB stick.
Switch on the receiver, at the rear, and then hold down the power button, behind the front flap, near the USB stick.
Once it says formatting stop pressing the button and let the image load.
At the completion of loading it should re-boot, at which point you can remove the USB stick.
After it re-boots it should have a GUI screen, (User Interface), allowing you to configure Blackhole.