Third page, second level

Why does this page appears as the third in the menu?

Because it has been the third one to be added below the "Content" page, at the first level, or because it has been moved to this place.

HOW do I move a page between others in a level of menu ?

As Explained in the user's guide, moving pages is easy: use the arrows of the top SiteNOTE toolbar and you'll see the menu adapting automatically. Do not forget to publish the page once it has been moved in the menu, so that this move is active in the online version of the site.

Why does a popup page open in this screen

a popup object has been inserted in this page, that points to the hiden sub-popup-page. This triggers automatic opening of a popup window if your popup blocker settings allow that.