Air handler turns on even when set temp is reached
I have a picture of a similar units wiring diagram, your unit might have connection for an optional outdoor thermostat - W2 on thermostat via outdoor thermostat to brown wire on air handler (if the outdoor thermostat is optional on your system - the diagram on the panel will tell you) and it will also describe how to install with out the outdoor thermostat by connecting the brown and W2 white leads together.  Again the panel has a wiring diagram - take a good picture of it and post it everyone can be much more helpful with that.