You wire a plastic Nest bracket up[0], the bracket redirects the inputs, and when you place the Nest into the bracket it makes the correct contacts with the back of the thermostat.<p>Wiring up a Nest isn&#x27;t too bad, you just need the precious C wire. Most of these fancy thermostats require the C wire for electrical power, and many homes lack it. They have a work around, but it requires re-wiring and you lose some functionality (do not recommend).<p>PS - No idea why nobody offers an AC adapter as an alternative to the C wire. All the C does is provide electrical power anyway...<p>[0] The middle white thing: <a href="http:&#x2F;&#x2F;i.imgur.com&#x2F;kNUPqvF.jpg" rel="nofollow">http:&#x2F;&#x2F;i.imgur.com&#x2F;kNUPqvF.jpg</a>