How do I switch between heat and cooling modes on the T4 Pro?

First, unlock the thermostat by pressing the center button and entering the passcode (default is 1234) using the Plus or Minus buttons, then press Select. Next, press and hold the buttons for about 3 seconds to access advanced settings, navigate to "TEST" using the Plus or Minus buttons, and press Select. Then use the buttons to choose the mode: "Heat," "Cool," "Fan," or "Em" (emergency heat), and press Select to activate the desired mode.