I like to think about layers like paint, except more versatile-- cause you can move the layers around. I have Corel 4, so maybe there are differences between that and X3.
My best advice is to play around with all the tools and layers. I did a whole bunch of terrible pictures and went through a lot of frustration before I kind of knew what I was doing. You just gotta give yourself time to get used to the program and then own it.