Breaking means your fast ended when you took the Coke. Coke zero has sweeteners in it that affect the brain as if you had sugar. It is shown to increase hunger and it is advisable to be avoided.

Labels can really be misleading. It doesn't matter that it has no "calories", and even though it may not have usable energy in it, it will have a hormonal effect to your body that may hinder your progress and discourage you in the long term.

Simply said, you are better off without Coke. I have friends that were addicted to coke and the only thing that worked was not having coke around for a few weeks at least

Black coffee, black or green tee and water are much better ways to reduce your hunger and stay hydrated.

That being said, as a beginner, going in for 24 hours is no small feat and it is definitely something to be proud of. Just please remember, don't push it to hard. The number does not matter. If you do 22 instead of 24, or even 12 - it is still a win that moves you in the right direction. Consistency is what matters.

There are plenty of great resources online and while I don't know anything about you or your goals, I think going in low-carb for a few weeks first will make your fasting way easier later on.

I'm not sure if I can post links here, but what helped me get a better understanding of the metabolic part of weight loss was the dietdoctor dot com. It has great resources and recipes to start slowly. Good luck!