Reinstalling the tiny little springs was a nightmare, but I got it done. I found it easiest to turn the headset upside down so that gravity would hold the spring in the right orientation. The rest was patience, dexterity, and a lot of luck...

The guide is much appreciated. I'll take better care of this new battery lol

I forgot to put the tab and tape back on the screen connector though, and I don't want to pull the screen back off, so I just have to live in constant fear of it coming out. FAFO.