Hi @claudiacavallin,

You can group pages together under a menu this way:

Create a new page, but under the settings​ of that page tick the box to make it a non clickable menu item. Then drag the pages you want together under that page and lastly drag each page slightly right. 

That will cause them to look slightly indented in the page list and gather them under the one menu heading. 

Hope that helps.

Regards, Mark