1st be aware that opening up the motor housing voids the Bosch warranty as does installation of any speed delimiting device. The EU has mandated that manufacturers install software that will detect and report such a modification to a class 1 bike, so this is not recommended until the bike is older than two years. That said, step one it to take a Bosch crank removal tool and remove the crank on the left side of the bike. Then remove the three screws that hold the two sides of the motor housing together. Remove the left side of the housing. Then disconnect the three multi-terminals specified in the speedbox2 directions and plug them into the appropriate speedbox multi-terminals, then plug in the multi-terminals from the speedbox2. Then find a spot that you can fold the wires and lay in the box where it will not interfere with the cover when you replace it. Take one or two small zip ties and secure the speedbox to the exisiting wiring. Replace the motor cover, taking care to properly overlap the two sides of the cover. Replace the crank.