5 - 30 minutos
I have to commute and my car radio sucks so I use my iPhone.
Problem was that after a day at work there was not enough power left to pay music on the way home.
So iFixed it.
As I have replaces batteries i Iphone 3's this was easy.
Particually after seeing your instructions
Take it slow.
Don't force anything.
If it does not slip into place have a good hard look and see what is not sitting right.