Unplug the Bosch dishwasher. Never work on the interior of your dishwasher without disconnecting the power.
Open the door to the dishwasher and remove the bottom dish rack. Remove the screws that hold the float assembly cover in place. Set the screws and the float assembly cover aside in a safe place.
Grasp the float assembly by one corner and pull it out of the dishwasher. The float assembly is designed to simply snap in and out of the Bosch dishwasher.
Insert the new float assembly and push on it until you feel it lock into place. Place the float assembly cover back on, then reinsert the dish rack. Plug the dishwasher back in.