The status light on the Apple TV should flash slowly during startup.
The status light on the Apple TV would glow continuously when it is on and functioning.
“No Signal” is typically a message from your TV that it isn’t getting a video signal from the selected input. Try disconnecting the HDMI cable on both ends, then re-connect. Try connecting the Apple TV to a different HDMI port on the TV. Try connecting the Apple TV to a different TV. Try connecting a different HDMI device to the HDMI port on the TV that the Apple TV was using.