Publishing you own book isn’t as hard as it might seem. First, you need to start somewhere. People write in many ways, but I suggest to my students to start with a Working Title, then an Outline.
Let’s say my Working Title is Dancing in the Forest.
Now, I would begin with an Outline, such as:
DANCING IN THE FOREST
Jody finds magical slippers in forest.
Slippers made Jody dance.
Jody was happy dancing in the sunlight in the forest.
When the sun set, Jody was still dancing.
The moonlight was pretty, but Jody was tired of dancing.
…and continue as far as you can go!