One way to set Tool Length Offsets is to run the TLSet macro, it will step you through the process, or use HDW - ZTool to do it manually.
While you are in HDW, you can set the work coordinates with the GxxX and GxxY buttons.
Post the Mastercam file with the Centurion post, use Util - Files - Load to get the program into the control - make sure the file is named O#### with no extension.
Execute the file with Run - Old, key in the number, follow the prompts.
The Centurion control really is an easy control to learn, you may want to consider getting a couple of hours of basic machine operation training from your local dealer to get you started... it would be money well spent.