Skip ahead to 9:19 in this interview to learn about a variety of ketogenic diets. In this interview I discuss the differences among them as well as some recommendations for getting started.
Simply put, the ketogenic diet needs to provide your body with enough fat nutritionally in order to enter a state of ketosis. On the low end, diets can include 60% fat, and on the high end - depending on your personal medical and nutritional needs - diets can include 90% fat. Adults typically require a diet on the lower end of the fat spectrum.
Because there is nuance to each person's individual needs, screening laboratory tests and/or special supplements may be necessary. For these reasons, I highly recommend consulting a physician and nutritionist before beginning a ketogenic diet. Eliminating sugar from one's diet is a safe and effective method to help prepare for the further carb resection of a keto therapy. There are several guides I've written for ketogenic diets that are available in the Keto Store along with other materials. All proceeds from the sale of these items go to The Charlie Foundation.
The Charlie Foundation also has an excellent list of resources for getting started, including hospitals worldwide that offer ketogenic support and specialists who you can consult with.