Hopefully you’ve done step 1 and are now ready to plan your text. 
You’ve probably already got the bones of your story written out, so it’s time to figure out if you’ve got enough content, too little content, and how it’s all going to fit together in an awesome book.
Things that need to be decided are:

• Word count
• Amount of pages

And then we can move on to page planning.
 
Word count
Consider 1,000 words to be your ceiling and aim lower. The exact amount of words really depends on your writing style and the story. I’ve worked on children’s books with as little as 280 words, and as much as 998 – and both of these extremes are amazing books. If you’ve already chosen your winning samples in step 1, you can use this to guide you.

Page planning
This is the last step in getting your text ready for the editor. This is crucial yet highly fun part of the book creation procedure. It’s where you plan the overview of your book. Below is the rough page plan of The Accidental Hero. As you’ll see, you don’t have to be an artist to produce page plans. Any funny squiggles will do, as long as they make sense to you. ​Repetitive layout (see spreads 8-9, 12-13 and 20-21) are an awesome feature to include.

So, there you are. You’ve written a good story and have great visions of getting it published. So now what? How to turn these words into a book?
My advice is to start with taking a trip to the bookstore. Seriously. A physical trip to the bookstore (obviously with COVID, this might be impossible, and then you’ll need to improvise). Seeing physical books on shelves and being able to touch them, feel them, smell them is a gift to anyone who wants to make a book. 
Look at books that are similar in content, length or have a similar target audience to the book you want to create. Hopefully one of the ones you pick up will speak to you, and you’ll be like, “This is it.” Or maybe it’s a couple of books – the size of this one, the binding style of that one, the paper in a third.
Then get intimate with the books you choose – take photos, write down their names, get their numbers, measure the size (you might need to buy the book first). 
I have a large collection of children’s books and I often browse them when I’m searching for inspiration.
What you are hoping to come away with after this exercise is:

1. Your book size
2. Binding 
3. Paper type

Binding:
There are three basic options when it comes to binding children’s books: 

1. Saddle-stitched, which is a fancy way of saying that the book is simply stapled together.
2. Perfect-binding (or PURR, which is similar), this is when the pages are glued together, and the book has a spine. Something to note is that this type of binding has a minimum page count of 24.
3. Hardcover, this is when the book has a … hard cover. 

If you are publishing through KDP, your only option is perfect-binding, which makes this an easy choice for you.
IngramSpark offer all three binding types, as will most traditional printers. The type of binding will naturally affect the cost of printing.