That is why you make Steaks not computers. Stick to what you're good at and studied for. Everyone in the whole wide world think they can engineer a computer system that suits their needs. Thus hundreds of boards like this open up.
mATX power supply is 400W only and specifically build for All-In-One motherboards, it is not enough to power a full ATX with components and extra drives. Trade it for a full size ATX, get at least a 600W PSU with enough amps to cover what you put inside the case. Warranty decides brand.