It's hard to find out what a CM education means, these days, because the idea of it has become fairly popular and lots of curricula, websites, blogs, etc. have picked up on key CM terms and may even call what they're doing CM, but aren't necessarily actually following Charlotte Mason's methods.
Also, a CM education changes dramatically over your child's life. In other words, what it looks like in preschool is very different from what it looks like in high school, and there are a couple of shifts in between as well.
During the preschool years, you focus on just a couple of areas:
* developing a love of nature by helping your child to interact with nature and observe it first hand. This builds a variety of skills in a developmentally appropriate way: fine motor skills, large motor skills, attention, observation, visualizing (making a mental picture of what you have seen, which is needed for reading and spelling), visual and auditory memory, and probably others I'm not thinking of. You could buy a workbook, or a whole curriculum, to work on these skills, but God designed the natural world to develop them in just the right way at just the right times.
* developing key habits that will help your home and school to operate smoothly. Choose one habit to form at a time and work on it for a month to six weeks. Once it's ingrained, don't neglect to maintain it even after you begin working on another. This will benefit your child throughout life because these habits will be second-nature and he will not have to even choose these positive paths.
Beyond that, just including your child in your normal activities (cooking, cleaning, working in the yard, etc.) actually develops the foundations for school much better than any worksheets or packaged activities. I sometimes use worksheets or packaged activities, but I do it because the kids find them fun, not because I feel the need to include them in our preschool. I used to use Montessori activities, until I read CM and realized that I could accomplish the same goals more meaningfully through everyday life experiences if I just intentionally aimed at those goals.
A Charlotte Mason education during the preschool years has more facets than just these, but this is a good place to start. Once you've begun to work on these areas, read Volume 1 and Volume 2, preferably with a group committed to understanding CM's principles. Choose one area to work on at a time, for yourself, and begin to add in more of the elements of a CM education little by little.