Quite a lot was covered in manipulating the Registry using API calls and VBA commands. The main thing to remember is to take advantage of the routines in the sample app so that you don't have to reinvent the wheel. Although it looks intimidating, after you get a handle on it, it's quite logical in the way that most calls require the predefined key, the path to the key, and maybe the value you're wanting to work with. Keep working on it and you will become quite proficient in no time.
For more information on API calls and linking databases, see these chapters: