Hi there,
Thanks for writing in! You need to set your layout to content with sidebar left or right. Then you can add a custom sidebar by going to Appearance > Sidebars.
Once you have created your sidebar, make sure you enable the post/pages you want the sidebar on and also check the
Enable sidebar on Shop Index page.
After that you will need to set your pages to the full-width page template layout, under page setting, when editing the page.
Hope this helps – thanks!