I'm not sure what is meant by training program -- the onboarding process is dependent on your team. The first day you are introduced to Microsoft is called NEO (New Employee Orientation). You get both a PM and a Dev mentor for your explorer team, along with your manager, who will help you throughout the summer.
During my PM rotation, I went to lots of meetings with my mentor. I really enjoyed this because I got to see what "real" PMs do! My mentor also showed me how to do pretty much everything else that is part of the role. The PM role is very different depending on which company you work for, or even which team you are on.
During my Dev rotation, I got plenty of time to ramp up on the tech I would be using. My mentor showed me how to set up my dev environment and what the daily workflow would be. By bothering my mentor and other teammates a lot (don't be afraid to do this!), I learned where to find the code I was looking for, and discovered other cool tools that seasoned software engineers use!