Once you add any custom template for a blog, product, or collection, they are not available directly into the backend customizer in Shopify.
In backend default templates are available, you need to assign the template to a page, product or blog and then navigate to the desired page, collection or product and blog page into backend using customizer window and then you able to edit the sections and blocks that are added to custom template code.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…