Writing doesn’t take free hours. It takes free minutes. This means that everyone has time to write. Yes, even you, because everyone has five minutes:-)
How much can you write in five minutes?
Let's find out. You may not have time to do this exercise immediately, but do it in the next couple of hours. You can even do it in your lunch hour, or in the car before you set off for home this evening.
Write for five minutes about the writing project you've committed yourself to.
"Writing about" is just talking to yourself on paper. It's free-writing, writing stream-of-consciousness style, without lifting your pen from the page. Just keep on writing. If you can't think of what you want to write, then just write that: "I can’t think of what to write next, look at that little boy over there with an ice-cream cone, I can't" etc.
How much did you manage to write in five minutes? A page? A page and a half?
If you write a page a day for a year, you've written a book.
If you've honestly got NO time, you still have five minutes here and there. Snatch five minutes from your lunch hour or get to a meeting ten minutes early and use five minutes to write. If all else fails, lock yourself in the bathroom and write for five minutes.