The details shared here apply to the most recent version of Turbo. To keep your theme up to date, check out this helpful document.
Enabling the Thumbnail Slider on the Product Page
This new option in Turbo is especially useful if you have many images for a product; instead of a cluttered collection of thumbnails extending down the page, they all get tucked neatly away into a slider below the main image. This will give your product pages a cleaner look while allowing shoppers to explore all of your product photos!
Please note: the slider will kick in when you have 7 or more thumbnail images!
To enable the Thumbnail Slider head into Customize > Navigate to your Product Page > Under Sections > Product > 'Thumbnail Position' select 'Bottom (slider).'
Just make sure the 'Show product gallery thumbnails' setting is enabled as well: