Open metal sliding top. Remove one individual Vcart and place on a flat surface, blades facing downwards. Remove old Vcart from your Shave with V razor by pressing on the white button behind the Vcart. This will pop the Vcart right out. Since your new Vcart is on a flat surface, press your Shave with V Razor against the Vcart in order for it to pop in. Caution if doing this step with your hands as blades are sharp and it can cause cuts to your hands and fingers.