Found these two vids on you tube
1)
https://www.youtube.com/watch?v=oJb0ELMFeUA
2)
https://www.youtube.com/watch?v=J-Xh9K_a9mA
There might be others, and also info on this forum
I'd take apart the donor mirror first - get practice and mark where the PCB fits on the mirror to help get the sensor alignment spot on.
Good Luck
Cheers
Bob