5
Go to the administration menu, select modules, click on the multimenu block and then you get a menu where you can ad new menu items (input title, link and so on)
Succes
Aloha
Ps: if you want a new page, you'll have to make that page first. That page can be an article you made in the news section, or a html/php page, or a custum block.
So first make this page and then place the link to that page in multimenu