I have the Intel build but I'm assuming it will be similar to AMD.
-Attach the clear tube to the hole at the top of the reservoir, then use a new clean funnel (don't want to contaminate the fluid), plug the funnel into the tube and just start filling it up. Make sure you hold the tube and funnel at a higher elevation than the hole the tube is plugged in to. Fill it up until the reservoir is almost full than power on the pump to cycle the coolant through, but make sure you power of the pc before the water level gets to the pump or lower, you don't want it running dry. Keep cycling it until the reservoir is full with a consistent stream of coolant going through the whole system without air bubbles.
To power on the pc , I had used just the power plug and didn't have anything else plugged in but the power cord. When pushing the power button to power the pump I would flip the switch on the back of the power supply to turn it off.