No matter how you create the part (in autocad, inventor, solidworks, mastercam etc) after importing the drawing into Mastercam, you simply use a post processor (specific to the mill you are using) to convert the toolpaths etc, into an NC file that the mill can load (which will be in mill-specific g-code, HAAS specific in your case).
You seem like you have learned alot already.
__________________
-Travis Covington
2008-2017 - Engineering Mentor of
Team 254
2001-2008 - Engineering Mentor of
Team 968
1998-2001 - Mechanical Director/Driver/Member of
Team 115