Please remember to soak the head to 15-20 minutes before the first time that you use it and physically feel the head for lumps or bumps, and if there are any use your hand to squeeze them out. The first priming is the most important because the head dries from the inside out vs. outside in like other mops. If you do not get all of the bumps out it can hinder the wringing ability of the mop, which will cause stress on the mop head and eventually pull it out of the back metal frame. After the first priming, soak it for a minute or two before each time you mop and you are all set to go.
Remove the old head. Line the holes of the head up with the holes on the frame. Attach the screws to the two outside holes first and then continue with the inside holes. By using this process it will allow for proper head alignment with the frame.