The aluminum case has 2 small holes in the back. It should have come with a syringe that you fill with distilled water and then put the water in each hole. If it didn't come with a syringe, contact Viper and maybe he will send you one. Unlike regular beads which you can see, the aluminum humidifier takes a little guesswork. Charge it up and put it in the humi. When the RH starts to drop, add some more. Soon you will realize how long you can go before a refill. Hope this helps.