CC925 I HIGHLY recommend joining the "Keto-Adaptation" group on facebook. It's a closed group, so your friends and family wouldn't see it. People there have great success. I tend to be more primal with my eating, but I believe in keto!
The percentages are based on macros. Everything we eat is either a carb (4 calories per gram), a protein (4 calories per gram) or a fat (9 calories per gram) - these three are your macros. Plug your stats into a
Keto Calculator and then you can see your percentages and the calories of each macro that you're aiming for.
A lot of people recommend getting used to the foods for two weeks or so before you start tracking. Basically you would just be avoiding all grains, legumes, sugar, starchy vegetables and adding more fat into your diet. How you'd like to start is up to you. Personally, I find it easier to plan my days ahead of time so that I'm not ever wondering what I'm going to eat and "winging" it without knowing if it fits my macros. I use
www.myfitnesspal.com to track, but some people like chronometer or some of the other apps.
Some people get into ketosis very quickly, but it takes time - up to a year or more - to truly become fat-adapted (burning fat for fuel instead of glucose).
In terms of speed - anything you lose will be better than not, right? I'd focus on the goals instead of the speed. Many people who have had difficulty with standard diets in the past really like keto because of the allowed foods. Fat is satiating so you may find that your hunger naturally dwindles.
Good luck!!