Before ordering your project, it's always a good idea to check your spelling. The program will check the spelling and let you know if it finds any words not in the internal dictionary. You can select the option to "Review Spelling" and correct if needed.
The Spell Check dialogue box will go through the misspellings one by one. You can choose to click into the text box and correct as needed, or you can click "Next" to skip that word.
Since the spell checker won't be able to tell if it's the "write" or "right" version of the word in the sentence, it's always a good idea to have someone else go over the book to check for misspellings as well. The Share feature is a great way to share your project with others for review.