To fill it, just hold the metal part at the top and unscrew the plastic mouthpiece. Then, you can tip it 45 degrees and gently fill on the bottom edge from a bottle, avoiding getting any liquid in the center tube. Fill to just below the wicks, close it up and let it soak for a couple minutes. If you get any gurgling, remove it from the device and gently blow from the top onto a tissue. Good luck!