Hello Barbara,

The menu you have on your site has a lot of (long) text these are your pages.
The space you have created to fit these text's is too small or narrow. For that reason x5 automaticly creates the Hemburger menu (the square).
Make the pages and text more compact or / and make the space for the menu bigger.

Or choose a horizontal menu that is high, this way it will be in more layers shown and then you won't get the hamburgermenu. (multiple colums)

So in short play around with space of the main menu untill the content fit's it.

see also the help/quide:

https://guide.websitex5.com/en/support/solutions/articles/44001606118-how-to-use-the-menu-object