HVAC

So I need to hook up a new Heater thermostat which can control the system better. So i did that it didn’t work. Room heater panel off and they have the red connected to white and white to yellow.
Then the red and yellow going to old thermostat is connected red to red. White to yellow.
Is it easier to connect the wires right to panel then to thermostat. Or new thermostat has the RC/RH built in
What to do?