Plug all 3 of the HDMI inputs in to the HD-301 and the output into the TV. The HDMI input sources into the input connections and the output connection to your TV. The Orei HD-301 HDMI will automatically switch to the currently active input source if there is only one active input. If there are multiple active inputs, then you can select the input either using the included IR remote or using the select button on the switch. The HDMI signal from the selected input is passed through to the output HDMI connection.