First head over to the products page and view the table of products.
Find the product you wish to generate tags for, and hit the green 'Manage' button at end of the desired product row.
This will load you into a unique product page. From here you can see the basic information for the product such as title, image, tag counts, last generated, and last pushed.
You will also find two buttons on the right called 'Generate New Tags' and 'Push Tags To Shopify'. Clicking the big green 'Generate New Tags' button will first ask for confirmation before generating, and if approved will return a list of generated tags for you to choose from.
Once the generated tags have been delivered, you have the option to remove any tag that doesn’t meet the products need by hitting the little trash can icon at the end of each tag.
When your happy with the tags, you can either replace or append to the tags on Shopify by clicking one of the two buttons. This will then close the popup and refresh the tags table