The ram is very accessible, it even comes with a manual on how to install it. The hard drive on the other hand you’d have to open it up for. If you at any point decide the hard drive isn’t big enough, or you need more space, go external to avoid opening it up. If you must open it to upgrade, take it to an apple certified/authorized repair center so they can upgrade it for you. Plan ahead if you think hard drive is going to be an issue, customize it to be 500GB or something before you get it. The Ram door is located underneath the screen with a phillips screw holding it in place.