Summary: There is no limit to the number of Tablets (sub pages) you can add to a Slate page. Tablets can be created, published, unpublished, reordered, renamed or removed at any time.
You can easily add many Tablets to your Slate.
When logged in and looking at your Slate page:
Click the "Add a Blank Tablet" link to the right of your Slate title.
A new item appears (as New Item Title) in your list of available Tablets. (*note: it may appear at the top or the bottom of the list). 1 - Click the green edit button next to the title.
2 - Highlight the text.
3 - Enter your new item Title.
Click the "Save" icon Your new Tablet Title appears in your list of available Tablets.