That sounds about right. I’d start with being able to drive the leds. I assume you are driving the leds with the shift registers? If so then you need a variable (probably an int to get 16 positions so you have one position for each of the 10 leds). Next you need to have the software to write that variable out to the shift registers to drive the leds (this is basically the same as the tutorial that writes to the shift registers). Each bit in the variable corresponds to one of the leds being lit, so start by setting one bit in the variable at a time and see that it lights the associated led and turns it off when the bit is cleared. Once that works then you only need to change the bits in the led variable when a button press happens so that the appropriate led turns on and the other led turns off it was on as it will stay on if you don’t turn it off.