Then keep on reading. What size machine do you want to build, and what do you want to do with it? That will help to determine what size motors you need. Also, how much do you want to spend?
In LT, you draw lines where you want the tool to travel, typically the center of the tool. Save as a .dxf (v12 works usually works best), load it into ACE and convert to g-code. ACE will let you set the cutting depth on a per layer basis. If you want to cut at different depths, draw on different layers.
You then load the g-code into a machine control program. The most popular is Mach3, at www.artofcnc.ca It's free for running up to 1000 lines of g-code at a time. Mach 3 can be installed in demo mode, so you can learn how it works on your everyday PC. Download the latest version (1.90.081) and install. Near the end of the install, you'll see a checkbox that says "install driver". UNCHECK the box and Mach3 will be installed in demo mode. Watch the setup and tutorial videos on the website to get you up and running. Once setup, you can load g-code and run the program.
Mach3 also comes with a simple CAM program, called LazyCAM, which will also convert your .dxf files from LT into g-code. It can be found in Mach3's file menu.