Happily, the web is on the case. Check out this Pinterest page for a raft of free DSM-5 explain-the-different-and-get-you-ready resources. A few favorites:
- This DSM-5 sample questions book, free (in part) on Google Books.
- This collection of additional resources at SocialWork.Career.
- These DSM-5 fact sheets from the APA.
However overwhelming it may seem, trust this: you'll get it learned. Most of the 5 is the same or very similar to it's Roman-numeraled predecessor. The big changes are few and summed up in a single article like this one from PsychCentral.
Fear not. It's big, it's new, but it's really no big deal. Have fun with it and good luck on the exam!