If you are using both the 2 clap and 3 clap receptacles, the combined total wattage cannot exceed 400W. Plug switch into the wall socket. Manually turn appliance on -- the indicator light to the left of the "II" will glow when the appliance has been manually turned on, but is clapped off. You can now turn on or off by clapping. You don't have to clap very hard. The clapping sequence is more important than how loudly you clap -- when each pause is approximately 1/2 to 1 second long, the three pauses after the second clap are very important since the switch must determine that you are not going to clap a third time.
If you clap a third time, the appliance connected to the two clap receptacle would not activate.