What do you do if you want to have a link to an external website in the menu?  This is easy.  The first thing you need to do is create a page. 

Once the page has been created, click the Settings button in the top left of the control panel.

Next, you expand the Advanced settings section and scroll to the bottom.  There you will find a section called Link Url.  Choose the URL option and type in the website address you want the page to link to in the field that appears. 

Now whenever someone clicks on that page from the website's menu they will be redirected to the new site.