Adding columns within pages

Hello,

I am a newbie and need some help with basic formatting. Within each page, I would like to add a right column (Ex. The ‘Testimonials’ column to the right of ‘About Us’ on the site https://themeforest.net/item/cleano-studios-wordpress-version/full_screen_preview/83537

Thanks for your help!
https://www.360nourishment.info