Which image are you trying to load?
Most images load the same, ensure you download the correct version, labelled VU+Solo SE, once unzipped you should have a folder entitled vuplus, you load this onto your USB stick.
You then power off the VU+ Solo SE, using the power switch, on the back. Insert your USB stick and switch the power button back on.
The white circular ring on the left side of the front panel will blink a few times then begin pulsing.
The pulsing indicates it's flashing the image.
Once the image has successfully flashed the pulsing will stop and change to blinking on and off.
When the white circular ring is blinking on and off it's now safe to power off with the switch on the back and remove the USB stick.
Power on again to reboot the receiver.