My battery had degraded to the point of lasting half a day.
Everything went well. I had to watch the video a couple of times and then kept it open as a guide. once I oriented myself it was not to bad. Getting the old battery out is quite the chore. I kept prying on it and it eventually released. I did not use any heat, just prolonged pressure on the blue pry bar.
There was not an adhesive strip included with the battery. Double stick tape would probably work. I pulled the adhesive off of the old battery and stuck it to the new one.
Turn your phone off... Seems like that should be a no brainer but... I used the tray the battery shipped in to hold the little screws and brackets. You could label and use some tape loops to keep things tidy if you wish. The instructions State you run the battery down to 10% and then charge without interruption to full charge. When I turned the phone back on it was at 50%... I watched YouTube videos with the flashlight on until I go it down to 10%. Took a while.