This code will automatically "split" an article into tabs, using "Header 2" headings as the split points/tab headings.
First, create a new snippet by visiting Library > Snippets, name it 'Tabs' for example, switch from WYSIWYG Editor to Code Editor, and paste the following code in:
Finally, save the snippet, and copy & paste the snippet merge code value at the top of the article in question. You can also insert the snippet at the top of your article by using the 'Insert Snippet' option in the editor instead and voila! The article should now be split into tabs at each H2 heading once you save it.
Make sure that the snippet merge code is free of any header formatting after you paste it!