Hello Sitruc! I do apologize, but it would be difficult to provide wiring instructions without knowing a little more information about your HVAC equipment. However, I can advise that this thermostat does require a common (C) wire dedicated to power the thermostat. With most thermostats, the wiring should just transfer to the new thermostat. For example, lettered terminals R, W, Y, G are the four wires needed for a one heat/one cool conventional forced air system. These terminals would be the same on the new thermostat as well. Then there would be the additional Common (C) wire would make the total number of wires connected five. For additional assistance with installing your new thermostat, please feel free to contact Honeywell Technical Support at (855) 733-5465. Thank you.