With a quick look at the code, I’d probably use the entire sketch so everything works as they expect it to as that should work under any conditions. If you don’t want the microstep functions you could omit that part of the sketch and modify the if statements to not execute the omitted parts, but if you are new to coding it may be easiest to start with the whole sketch and once that works (so you know everything is ok) then change the code and see what breaks (which can range from no longer compiling correctly to compiling but working oddly or part not working). The usual reason (other than being sensibly lazy and not wanting to type too much code in 
) to omit code would be because the sketch is too large to fit your processor but that isn’t likely to be the case here if this is the only thing running. I prefer to start from something I know works (so both the hardware and the software are known to be fine) and then make changes from there.
Peter
