It is very easy to do. Simply follow our first two MPLAB XC8 Tutorials, if you want to do it without using any interrupts. The only thing that you need to take care is the LAT register. PIC 18F microcontrollers have LAT register to solve Read Modify Write problems. So for writing data (controlling LED) you need to use LAT register instead of PORT. But for reading data you can use PORT as before.