Full width content in theme with sidebar

[ Moderator note: moved to Fixing WordPress. ]

Hi all,

I’m building a website for a friend (link here https://marymiers.com/).
The theme (I believe it’s called prana) is fairly minimalist, and a good base to work on. But I want to add a full width slider on the home page, and cannot work out how to bypass the theme layout which always allows space for a sidebar.

Any help, as always, much appreciated.

Iz