A:Answer The Sensi Touch 2 thermostat installation instructions are detailed with illustrations and I think very good WRT wiring. Just take reference pics before dewiring the old thermostat being replaced. Additional online YT videos are also always available. It helps to study up a bit on thermostat wiring tutorials (easily found) before you start so you have a basic thermostat wiring knowledge. ALSO, maybe check & photograph the wiring connections on your furnace, AC, and any accessories (eg, humidifier). But basically, be meticulous about photographing your EXISTING thermostat wiring connections - having that as a clear reference is critical.