Sitecore Experience Commerce (How to add associated entity in case of No result found)

For adding a related product list, We need to associate product entity with the existing product, I was trying to add a product but couldn't find that product in the search result.

in this case, make sure to search the product by full entity name like  Entity-SellableItem-DN151254

even, in that case, you wouldn't see the result but just press the enter or yes button, You will see that the product has been associated with the current product.

that's how we search and associate entity.