The link above describes how to get started with an existing GC2. If you have a 3G module you will need to replace it with a 4G LTE module. Alarm.com no longer allows new account activation with 3G modules. 3G modules will cease to function at all in 2022.
Lennox iComfort is available per special request. It is not currently supported in our System Manager to allow enabling/disabling at any time, but we can manually enable it for you. Just send a message to us after getting started.