Note that this doc refers to Shoptimizer for BigCommerce. If you are looking for the WooCommerce version go here.
You can edit this via Appearance > Menus
– and choose Secondary Menu from the dropdown
First – click on Screen Options at the top and make sure that the CSS Classes field is ticked.
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Add the My Account link to the menu. Within the CSS Classes field: ri ri-user
Add the Customer Help link to the menu. Within the CSS Classes field: ri ri-question-circle
Add the Checkout link to the menu. Within the CSS Classes field: ri ri-chevron-right-circle
Want to choose different icons? No problem – see the full list you can use.