Your HDMI switch box operates in three modes: Auto-detect (default), manual, and remote control.
If in manual mode, press and release the POWER/SELECT button quickly to switch between devices. OR
If using the remote control, press the NUMBER button on the remote control corresponding to the device you wish to select.
NOTE: If manual mode or the remote control is used, the auto-detect mode becomes disabled.
How do I put the switcher back into Auto-detect mode?
Turn the switcher OFF, then ON. OR
Connect a new HDMI device.