From the support page of your Thinka you first enable Alexa Echo and then you will be able to pair with Alexa Echo. Your Thinka will generate a token that you use to enable the Thinka skill on your Echo. This way only your Echo can communicate with your Thinka.
Next go to the Thinka skill
on the Amazon Alexa site and enable the skill be entering the token from your Thinka.
Now click (or say) discover devices and you should see a list of devices available in Echo.