Hi Lena,

You can make any page a subpage of another by typing the slug of the parent page under the settings of the subpage.

The large boxes that appear on the top of subpages are known as breadcrumbs. They help folks navigate your site and refer back to a page, almost like a "you are here" icon on a directory. You can disable them by removing the following line of code from the layout of your pages. 

{% include "breadcrumbs" %}