When I took mine, it was a (2) part exam. First part was "rules of the road" and the second part was "navigation". The first part is straight questions and answers based on mariner rules, which can be studied in printed material. The second part is navigation scenarios where they give a situation in navigation and you respond based on the "proper procedure. Also have to identify lighting, buoys, markers and types of vessels and etc. I ordered a study guide and did it with a friend. The prep courses would be a better route, I think. Don,t know the cost now, but won't be hard to find out. This has been many years ago, but I,m sure the current exam is similar. You also have to take a physical and log your "on water" time. Typical goverment type testing. However with experience and prep course, you shouldn't have too much trouble. It also will help on insurance. Good luck.
Capt.C........Life's short. Be a friend. Eat good. Have fun and fish hard!