Set track 1 to [Up], track 2 to [Down], track 3 to W, and track 4 to S. By doing this, you only need press [Up], [Down], and W or S. You can only press W or S and do not need to press both of them. For example, when you need to press W you can press S. You can change tracks 3 and 4 to other letters but do not change 1 and 2.