I replace my iPad mini 4 screen-digitizer and did not have to replace this sensor because it did not have one, but the new screen-digitizer came with the sleep/wake sensor in place. Small electronics needs careful and tedious work. Thanks iFixit for the instructions to fix my iPad. I have to mention that I am a technician from the old school.
Pretty easy to follow instructions if you have patience and careful hands. If you have clumsy hands you will not succeed in fixing any small electronics. There are some small things you should use to help you succeed at fixing small electronics, like some scotch tape or other clear tape to hold some of the cables in place while you work on small electronics items, also a small heavy bottle or object to propped the iPhones cases against to hold them from falling over so that your hands can be free to perform your tasks. Great job you are doing iFixit personel and I am with you all the way with fighting for our rights to fix our electronics equipment.