“I'm writing a book. I've got the page numbers done, so now I just have to fill in the rest.”

Simplified Meaning:

Imagine you want to make a big, complicated dinner. You've already set the table and put out the plates, but you haven't actually cooked any of the food yet. The quote is like that. It means someone has done a small, easy part of a big job, but they still have the hard, important part left to do. For example, in school, you might write your name and the date at the top of your homework. This takes just a few seconds. But then you have to do the whole assignment, which takes much more time and effort. In everyday life, this idea teaches us not to celebrate too early just because we completed a minor step. It reminds us to stay focused on the bigger task until it's really finished. So, when you start a project, remember that the small steps at the beginning are just the start, and you need to work hard to finish the whole thing.