The following article demonstrates how to add enabled the Slidey Bar embedded app in the new section supporting (OS2) themes in Shopify.

Important Note: To display the Slidey Bar and its content requires both the Embed enabled and a Slidey Bar section  content block installed. Click here on how to add a content block

Open your Theme Customisation menu and on the left side click on the  'App embeds' option

Select the Slidey Bar app embed and toggle enable and click Save