This question is somewhat answered in the book "How to write a book", here: http://www.writerbabu.com/book/how-to-write-a-book/1/, here we will explore step by step the process of book writing.
So when you are on Writerbabu and you have logged-in( after signup of'course) you have to go to your Books Dashboard to start your memorable journey of book writing. You can find link to book dashboard in the navigation panel (click on the right of your name in the header). The link to books dashboard is also there on the book section main page ( http://www.writerbabu.com/books.php ).
Step 1: Creating The Book
On the book dashboard, you can find a big text field for book title and a category drop-down at the starting of the page. Enter the title of your book, choose a category and hit the submit button. The book has been created and you are now on the book writing page.
Step 2: Adding Chapters
Now you will see no chapters but a small text-field with a submit button having text "Add Chapter". It does exactly what's written on it. You enter the chapter name and hit that button, the first chapter has been added. You can now see various option for the newly added chapter. You can now write the chapter by clicking on the "write" link. You can delete the chapter and you can edit the name of the chapter using the options in front of your eyes. So similarly add as many chapters as you want one by one in the order you want them to appear in your book.
Step 3: Writing Chapters
In front of each chapter's name there is a link "Write", click on that and start writing the chapter content. The form auto saves what you have written every 5 seconds.
And hence slowly you will have written the whole book
Step 4: Add Book Cover Image
By the side of the chapters there is a default cover of your book. Just below that cover is the option to upload your own book cover image. You can choose any image from you laptop/desktop/tab upload and crop and set it as your Book cover.
Step 5: Set A Price
Now that you have put so much of your effort and time you deserve some value for your hard work. Just below the image upload option is the option to set the book price. You can set it to any value that you think would be suitable for your book and that people will buy and read it. You can leave this part to keep your book free.
Step 6: Publish
Although this chapter is just about writing a book, it will not hurt to mention that you can publish you book by clicking on the big publish button near the "set price" button. You will be asked to pay a small sum of Rupees 100 ( less than 2 USD ) as a publishing fee. You can pay through credit card, debit card or net-banking options.
That is it. Now your book is available for everyone to buy and read. Its time to collect feedback :)