As previous reviewers have written; watch a video or two, work in good light, stay calm, be intentional (in other words stay calm and don't freak out), don't misplace the tiny screws

Fortunately I had watched enough youtube videos of how to replace an iphone 6 battery that the insufficient instructions in the package didn't matter.

Instructions are so tiny that you can't read them without a magnifying glass but their are excellent videos online