I was successful in leaving the display assembly attached and simply used a rubber band to hold it in a vertical position against a stiff box. The steps starting with #17 and their reverse steps can be omitted.
For me, removing the battery was a battle because I couldn’t get a grip on the adhesive bar at the end of the battery. I just used some “gentle” persuasion and a little heat to make the battery give up. Once it was lifted a bit I could get the adhesive strips to stretch in the classic wa. The battery was worse for the wear.
I didn’t know what orientation the clip for the home button should be so I just clipped it into place.
You do need good light and, if possible, a head-mounted magnifier.
Be careful when plugging the new battery in. Be sure it is properly aligned and seats with a satisfying click.
The worse step was pulling the front glass off. It takes time and eventually gives up. Just keep pulling. I had to clean the glass and suction cup with denatured alcohol to achieve a good seal.
Some articles show removal of the SIM card holder. Is this necessary?
Dec 26/ 2019