Config page display design tool same this url https://demo.tshirtecommerce.com/prestashop/design-your-own
- Login to your back-office
- Go to T-Shirt eCommerce > Prestashop Settings
- Find field “Product Designer Page“, choose page and save.
You should create a new menu link or a new button link on front-office with your theme and then try set link to above url.
You can refer with our video below: