1. Simply push and slide open the cartridge door at the bottom of the unit. 2. Fill the oil bottle with essential oil. 3. Screw the wick into the oil bottle. 4. Insert the oil bottle into the cartridge compartment. 5. Close the door, plug it into a USB port and the diffuser is ready to use. 6. Diffusion interval settings: ever 10 seconds, 30 seconds, or 60 seconds. 7. The USB Diffuser light flashes when it is diffusing oil.