It's a pretty simple design but you have to keep a few things in mind before you start. First you need to buy a second wall charger because you will be gluing the connector in place. This makes it unusable without the dock. Actually I have not yet glued mine in place. I make the connector hole very snug and it works pretty good but glue will work better.
The next issue is that the thickness of the iPhone changes if you use a case. You need to modify the gap between the connector hole and the back support to account for this difference. It's not difficult but make some test fits before you glue everything up.
Look over the picture good before you start the project.