You will only need to port forward your thermostats if you are going to try to access them from outside the LAN and want to communicate directly with them. If you are unfamiliar with how to do port forwarding you can go to portforward.com for step by step instructions.  If you cannot find instruction on portforward.com for your router refer to the users manual or another online source for instructions. If you are planning to use the CloudConnect service you do not need to port forward your devices to access them from outside the LAN via the cloud service.