Note: This is my experience of the HSP D5 Handgun course as an individual who has only began shooting a handgun for ~3 months.
If only one thing:
If there is only one thing I could stress to those who are potentially interested in this course, it will be 
“don’t be intimidated”. Don’t be intimidated by your own lack of experience. Or, don’t be intimidated how much better the other students might be. I have only been shooting for 3 months by the time I attended the course. And at no point did the instructors or other students made it uncomfortable or intimidating for the less experienced in the class. If anything, everyone was ultra-encouraging and very willing to share their knowledge and experiences.
There are other sources on the internet where they would go through what happens in the course day-by-day, so I won’t go over that. (it will be listed at the end of this post)