Unpublishing your pages within Shogun is super easy. You can find this option in the 'Page Settings' under the three dots menu.
Provided the page's current status is 'Published' you'll find a button at the top of that pane to 'Unpublish' the page.
The option will also appear on the page list in the main Build menu, if you prefer.
Note: in the event you want the content to revert to the presentation as found on your eCommerce platform, you should consider reverting the import instead, as unpublishing a page in Shogun will also unpublish the page on the platform.