HELP!

Engireland

Hi I am completely new to embedded C programming. In college I have being given the task of programming a pic 18f4620 to switch an LED on and off, simple as that. I really have no clue where to start, we were provided with an example code that just turned the LED on and off with a slight delay that can be adjusted, all inside an infinite loop. I need to modify this programme to include a sitch to turn the LED on and off. I was told things like instead of using LATD use PORTD and also to include a TRISD command in the code but I have no idea what to do from how to connect the switch into the pic to even getting started with the code. Any help would be greatly appreciated