I got through this successfully and it solved my problem (phone wouldn't charge/iTunes wouldn't recognize it when plugged in). With the new part it works perfectly.
Two cautions: I bought a new lightning connector assembly and I had to transfer two items from the old assembly that were not mentioned in the steps.
(1) There is a small black rubber "boot" which you can see in the step 38 photo. (on the very bottom between the lightning port and the headphone jack) Pull this off and put it in the same place on your new lightning connector assembly. It attaches to a fitting on the bottom wall of the aluminum case.
(2) There is a bracket that holds the home button connector socket in place. This is the socket that is exposed when you disconnect the home button cable in step 9. When you remove the old lightning connector assembly, this bracket needs to be transferred to the new assembly. It's attached by a small piece of double sided tape that you can salvage/reuse if you're careful!