Every display is different and the information below may be different to your display, however, this is how to enable HDMI-CEC on popular displays:
LG
Settings > General > SIMPLINK > On
Settings > General > SIMPLINK > enable auto power sync
Samsung
Settings > System > General > Anynet+ (HDMI-CEC)
With HDMI-CEC enabled on your display, you can now use the HDMI-CEC control features within embed signage on your compatible device(s).
