To publish a manual, the following conditions must be met:
At least one step is registered
In addition to the cover, at least one step is required. If there are no steps, the message "Please create at least 1 step" will be displayed.
Title and image (or video) are registered for the cover and all steps
If they are not registered, the message "Some areas have not been completed" will be displayed.
The title and description text are within the character limit
If the limit is exceeded, the message "Please enter within {x} characters" will be displayed.
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Related: Why does the 'Missing required fields' error occur even when the publishing conditions are met?
https://help.teachme.jp/hc/en-us/articles/900005509566
Related: What is the character limit for the title, description, and other text fields?
https://help.teachme.jp/hc/en-us/articles/900006444683