First build can be but make sure to take note of how your dad does it and you'll learn easy enough
Building computers is mostly about making sure everything is plugged in properly, nothing fits where it doesn't go!
Would I be able to return it though? as this is not the only problem we have with it atm, we may need to get an adapter, as the power supply cant actually connect to the motherboard, it need a 6 to 4 pin or somthing.
What would be easiest?