How do I add custom tabs on product pages?

I would like to add a custom tab such as size chart beside the Description on product pages. I have not found an add-on for this. Thank you in advance.
You could fill in the atributes and this would give a new tab.It will give a strong tekst.
Edit includes/templates/*.catalog/views/ LiteCart emulates Bootstrap 3 Tabs so you can easily find a how to guide.