First, Dcal is a program for modifying a calibration, so is ChEM. I use both, because they both do some things well, but not everything, so sometimes I need to use the both on a calibration.
Ladybugg, Turbonator, and Blueberry are some common names for actual calibrations.
The modifying of cals is pretty easy and straight forward, the kicker is knowing WHAT to modify. I still havent figured that out, well, past upping the boost or changing injectors hehe
If I were you, I would get a burner, some chips, and a socketed LM installed in your car, then burn some basic (known good) cals. Once you can do that, then you can play with things a little here or there to see what the effects are. Use Chem or Dcal to mess around with all the aspects of the calibration.
IE learn by doing. Just dont blow anything up mkay!?