Go to the HELP menu in the upper right hand side. Under documentation there is a MTD user guide located there.
This will walk you through every stage of creating and modifying MTD's and how they work.
I don't have 4 axiz rotary machine
Try creating a case with Autodesk support and request if they can send you what you need. If you read this post @TK.421 was able to get what he needed by requesting it
Does anybody have Makino a51nx .mtd file? Please help providing if anybody has.