Very nice experience for first time (critic) user.
Fast battery death. The battery would lose 20% of its juice, each time I looked at it! It wouldn't last through the day, and frequently fell below 20% or to 0 by noon.
I watched the video twice (okay, three times), and easily got the screws out of the base and cover off. The two small Phillips screws to the battery connection were difficult until I changed to a LARGER driver (counterintuitive).
Overall, very satisfied with product, packaging, encouragements, and yes. . . results!
It's in the instructions but. . .
One surprise (unpleasant) was that when I pried straight up on the connector to the battery, the little contact with the gold finger that's held on by the same screw (the upper battery screw), slid away and it took a while to read and re-read the how and where and why of where it went. I worried needlessly. Gold tip goes up, so it can touch the back of the phone when you reinstall it. May need better photo and description on the website. One advantage. . . is that you can 'spring' the finger slightly up to make a great contact with the back and maybe even get an improved performance from previously experienced if it was worn.