Could you please provide more details about the issue? Can you maybe provide a screenshot and URLs to affected pages?
If you would like to display a sidebar on a page, please note that the theme does not contain such layout (page template).
But maybe a fast and simple solution would be to create a product tag of “Upcoming sales” and then assign it to some products. Than you can add a link to this product tag archive page into your menu. That way the layout is the same as on shop page. (Something like https://themedemos.webmandesign.eu/angelica/product-tag/biography/ in theme demo website.)