you missed the part about the two usb cables .... one for power(the red one) and one for usb stick
No I didn't
There are two USB cables because one USB socket on the PC might not be capable of powering a 2.5" drive, so the second is used to provide extra power that may be needed.
You seem to be missing the point that power is supplied FROM the USB connectors, to the IDE connectors.
Your flash stick does not supply power.
It is highly unlikely that with the IDE connecter attached to a motherboard there would be any power going out on the USB cable.
It would be bad design and potentially dangerous if it did!
If that were the case, then the power from the external PSU in that video would be fed back INTO the PC USB socket!
If I were to attempt it I would get a cheap IDE to USB converter, cut the power wires of the USB cable, apply power to those (at the plug end), attach a female to female USB adaptor to the end and plug in the flash drive to that ......... and then hope for the best.
Care would have to be taken of course to ensure the power was applied correctly as reversing the power could kill the flash stick.
If someone ever gives me one of those cheap adapters I may just try it