Bottom line
If you are a Reserve Marine selected for the Naval Academy Preparatory School (NAPS), the prep school that gets you ready for the U.S. Naval Academy (USNA), this section covers how your orders get written, who writes them, and what your status is while you are there. At NAPS you are on active-duty enlisted status, that time counts toward pay and retirement computations, and if you go on to the Naval Academy you are discharged from the USMCR and accessed into the Navy as a midshipman.
What it means for you
This is a narrow path that applies if you have been selected for NAPS. The practical points: your parent command (or MCIRSA if you are in the IRR) writes your orders, you check in at Newport, Rhode Island in your Service "A" uniform, the school provides your billeting, and you should get a DD 214 for your NAPS service. If you make it to the Naval Academy, you stop being a USMCR Marine and become a Navy midshipman.