Every plug-in vehicle manufacturer would like for us to believe that its own charging solution is the best option for its plug-in vehicles.
BMW is no different:
"The BMW i Wallbox is your most convenient private charging option for your BMW i3 and i8. BMW i offers you a customized installation service package including Wallbox Installation Survey, delivery and installation of your BMW i Wallbox."
"Since every private parking situation is different, BMW i offers you an Online Pre-Check to see whether the BMW i Wallbox generally can be installed at your home."
Honestly, we'd skip the Wallbox and go for perhaps a ClipperCreek unit, but if the Wallbox is what you desire, then you ought to check out this BMW i Wallbox video.