My Apple TV is not working just blinking what should I do

If the light is continuously flashing then you will need to restore it via computer

Reset Apple TV - Apple Support

use your tv remote to make sure the hdmi port the appletv is connected to is the one set as active input source

if it is

disconnect it from ac for 30sec

if that does not work

try another hdmi cable and make sure it's fully inserted in both appletv and tv

if that does not work

try the appletv with another tv to verify if the appletv is the culprit.