Hi,
Here's a step by step on how to do it, and get there support
1) click on Admin
2) Under Configuration, click on Style manager
3)Click on custom tabs at the end of the horizontal list along the top
4) Fill in the Add Custom Tab box, give a title for your page
5) Paste in the URL you want the tab to take you to
6) If you want an image displayed by the tab, then paste in an Image URL
7) Click add tab
And you're done - hope that helped support