Use a different page template for that page. 'Blank' would get rid of those areas, and more. If you want total control of exactly what areas appear, you may need a custom page template.

Thank you @Gondwana for your reply!

So if I change the template to CUSTOM, and then delete all elements on the header, including the navbar, that won't affect the pages based on different templates?

No, that didn't work, when I switched to custom template and deleted the navbar, the navbar desapeared from every other page...

The list of templates available depends on your theme. The 'Elemental' theme doesn't have a template called 'custom', but the theme you're using may do so. My assumption was that a new template would need to be created for your current theme, which involves php coding.

If you change the page template in the page settings for that page, it shouldn't affect any other pages. Nevertheless, this could be a good opportunity to back up your site.

As an alterative, you could probably hide the bits you don't want to see using CSS. However, that would be inelegant and slower to load.

Thank you... Css did the trick...

All the best,

V.