Fortunately, the Aurora R12 PSU is standard ATX format. Consider a fully modular PSU so any unused cables can stay in the box. Also, try to stay 140mm to 150mm long or it will start to use up your cable management space. These would be some options that meet that criteria: pcpartpicker 
As the heading says I have little experience of working with computers. So here's what happened, I was upgrading my computer with some new RAM. (yes the RAM works, and it's compatible.) Successfully installed two sticks of RAM before my PC couldn't power on anymore, 4 yellow flashes from the front light so it's definitely my RAM. I figured out it was my power supply which wasn't strong enough to support it. Decided to upgrade to an 850-watt power supply for my ram and graphics card I will be installing soon. Where do I even begin to upgrade it? I've done much research but couldn't understand most of the things I learned. Could someone help me with this? Thank you.
Aurora R12, help with PSU upgrade