design issue

Hi!

I want to change the design of our website to something similar for example to this site:

https://demos.uxthemes.com/layouts/blocks/about-page-fitness/

– where the design is all over the page.

I can’t do it on our site. It always puts it in a square, instead of spreading it all over the screen.

Can you help me change the settings on WordPress so that the new design can be all over the page (like the design is meant to be)?

Thanks!!