If you are new you would like to get staple cards first. Start from opening Ultimate Rising for Sphere of Kuriboh, then open Neo-Impact for Mirror Wall.
But yeah, opening Ultimate Rising/Neo-Impact is a very bad idea, they are powercrept garbage boxes, It's not worthy to get SK or MW from some bad box, not to mention SK and MW's popularity are really getting reducing, I think you should skip that part from the guide.