You'll need to remove the foil tab on the refill bottle before you start pouring. This tab secures the bottle and the wine inside until it arrives at your home and you're ready to open the bottle.
To remove the tab, puncture the tab with any pointy object (a pen or pen cap works great). Now you are ready to insert the refill bottle into your Kuvée bottle and start pouring (just make sure you also remove the cap before pouring. You can place the cap back on once you are done pouring).