the whole repair was quite straightforward. these alternative instructions were helpful at points: http://www.instructables.com/id/iPhone-6... as was this video: https://www.youtube.com/watch?v=mh-cbErz...

before finishing the last step of pushing the screen back into the body of the phone, I turned it on and checked all of the functions - the camera, the light sensor and the touch pad. The touch pad wasn’t working, so I turned it off again, and re-seated the home button cable. when i started it up again, it worked properly. Thank you IFIXIT.COM! and many thanks to all of the other folks who commented here.