Hi, and welcome to the forum.
You could start by converting a (10k lineair) pot position into a digital value.
Look at the "ReadAnalogVoltage" sketch that comes with the IDE (File > Examples).
With the "Map" function, you could change that into a "desired temp" range.
Then play with DS18B20 digital temp sensors. Much easier than thermistors.
An "if statement" could compare desired and actual temp, and select heating/cooling.
So far you have been printing to serial monitor.
Printing to LCD is not much different.
Post the code (and diagrams) you have so far, so we can check it.
Leo..