Directions for a honeywell thermostat t834c wire installation

To be sure, open the Air Handler to see which wires are used and to what, black may be unused?
Red is 24 volts, white usually heat, green usually blower, yellow for outside compressor(cooling).
If you touch the red to the green and the blower works, you have 2 conductors identified.
The Blower work with heating and cooling.