Why do you need product grouped?
Product grouped is a tool to help you group products together. Product groups are created to boost the number of products that customers want to buy when visiting your store.
If you wanna create product grouped, please follow here
Open a product page available, copy ID of that parent product.
Go to Online Store > Navigation > Add menu
You need enter fill these sections: Title, Handle & Menu Item, then click Save.
Note: When you set name of the Handle, please remember this syntax group-ID of parent product
Go to Products -> Choose Parent product -> CLick to View To see the result.