When the Thinka is starting up the LED is constant red. After starting up your Thinka will look for updates while the LED flashes red.
When ready your Thinka's LED should be constant green. Sometimes a Thinka will restart after receiving an update, and power off the LED for a short while.
In some cases even twice. If your Thinka is blinking green, it means it needs attention, most probably it has lost some connection.