I'm going to assume that you already know how to make enchiladas.
We took a pound of 90/10 ground beef plus all the other usual ingredients like onions, grated cheese and enchilada sauce, then made a layered casserole just like you would prepare lasagna, in a 9x9" Pyrex dish.
(I'm also assuming you have a passing aquaintance with the structure of lasagna).
Cutting the corn tortillas in half makes it easier to get their edges to cooperate with a square pan.
The main thing is that you don't have to fry the tortillas, or fill and roll them.
This cuts out a ton of prep time, so you're saying "Mmmm...oh my God...more!!!" at least half an hour sooner and the taste is pretty much the same.
Using tortillas that haven't been fried means less grease, which is good for you.