There are two APIs for the ADC: one is waiting for a result ready and the other actually gets the converted data. There are APIs to convert those digital counter values into a mV or V number.
Display? Which display?
You might take the chance to use the USB-UART bridge in your Development kit (I assume you have got one). Read the chapter in the Kitprog manual that was installed on your PC when you installed the kit software. The bridge together with a terminal emulation on your pc (as PuTTY) will let you send ASCII data to your screen. Use sprintf() for conversion, take care when using floats, there are some pitfalls.